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Monday, December 15, 2008

GM 3.8L Plastic Composite Intake Manifold



When car manufacturers decide to do something goofy, like using plastic intake manifolds, we in the repair business do not get happy feet anticipating a stream of big repair invoices. The customers many times see us as somehow connected to these breakdown time-bombs, wondering why we didn’t anticipate trouble, and force the manufacturers back on the proper path of metallic parts more resistant to problems. In actuality, we in the repair business love maintenance work, and would like nothing better than to service vehicles for our customers with all potential fiascos handled before they strand our clients. We are not always given this option, either because the manufacturers don’t broadcast their engineering snafus, or the customer ignores our warnings, which brings me to the pictures above of a GM 3.8L plastic upper intake manifold.
A metal tube routed up through the lower metal intake manifold from the Exhaust Gas Recirculation Valve burns holes in the plastic manifold it extends into, allowing coolant to be mixed into the crankcase engine oil and combustion chambers. Unfortunately, the signs don’t always become obvious until the coolant contaminated engine oil destroys the engine. This plastic manifold was used on most 3.8L GM engines from 1995 thru 2005. The fix, involving replacement of the upper plastic (composite) intake manifold, gaskets, and peripherals is costly; but much less expensive than replacing the engine, which will have to be done if this repair is not completed.
I had three of these in the last week, which is how things go wrong in auto repair: in threes. The first engine was already ruined. The second made lifter noise in the morning, and was salvageable, as was the third. The first customer had driven the Pontiac from back East, which is much harder on the manifolds due to extremes in temperature. He said he had experienced no sign of failure until the vehicle simply quit on him. I figured if I put this out on the blog, it might get picked up in the search engine, as was my Honda Balance Shaft seal blog, and save some engines. When the hood is opened on one of these, you will not see this manifold. There is a plastic cover over the entire engine, which says 3.8L on it. It can be removed by unscrewing the oil filler cap and tube (counterclockwise). This allows the engine cover to be slightly tilted and freed from the rear fixture. Then the plastic intake manifold will be visible.
That’s all for this update from Nilson Brothers Garage, but if you’re appreciative of the information, here is a link to my new novel COLD BLOODED for Nook and Kindle. If you’re kind enough to read it and like it, please review it on the site you purchase it from. Thank You! Every little bit helps my writing gig. :)

220 comments:

1 – 200 of 220   Newer›   Newest»
Charles Gramlich said...

It even sounds like trouble in the offing. I better check mine.

BernardL said...

If it's a 3.8L GM, with black plastic manifold under the engine cover, look through your maintenance receipts just to make sure it hasn't already been done, Charles. They've been known to go out in under 50,000 miles back East. In our San Francisco Bay Area, they're usually safe up to 90,000 miles. If it needs to be done, it's a great time to have the throttle body cleaned out while the manifold's changed, and the cooling system flushed with whatever hoses look bad replaced.

If you see any milky type creamy substance on the underside of the oil filler cap, that's a dead giveaway coolant's seeping into the oil.

raine said...

Huh? :-)

Um...ok...why aren't the manufacturers paying for this 'mistake' as a recall of some sort?

BernardL said...

They did in a class action judgment a little while ago, Raine; but it's over, and there are a lot of these cars out there. They did warranty them if the manifold failed in the first five years or fifty thousand miles.

GM put these plastic composite manifolds on to lighten the vehicle to meet federal gas mileage demands. Ford has had their troubles with plastic manifolds too and legal battles. I guess they don't recall them; because if they did, the vehicles wouldn't pass federal EPA standards. Plus, they have so many out there now, it would bankrupt them quicker than their union contracts are doing.

Virginia Lady said...

And people wonder why Gm has been having problems selling cars. This kind of repair is likely to turn someone off of their cars forever.

BernardL said...

The short sighted decisions like this from their engineering department, and their incredibly stupid union contracts are killing them.

Anonymous said...

BernardL: Can you tell me more about the class action judgement ? I had this repair in 2004 on my 1999 Grand Prix with only 48K miles.

BernardL said...

I'm sorry Anon, but my customer who checked up on it told me it's over.

Anonymous said...

Thanks Bernard

Matthew Nowlin said...

I sell a ton of these engines because of exactly this problem. Like you, I don't like it. It's one thing to sell an engine to someone who abused/abuses their car. It's another thing to sell an engine to a family that babies the car they use to haul the family around in and get to work.

BernardL said...

Matthew, they run great but... why any of the manufacturers went with plastic manifolds is a mystery.

Matthew Nowlin said...

Well, when we sell these 3.8 Series II or a 3.1 up to '03, we require the customer to replace their IMA gasket. Like your post says, that eliminates 99% of the problems with these otherwise great engines.

BernardL said...

It is very good insurance to prevent catastrophic failure, Matthew.

Jeremy said...

I have a 2002 Grand Prix GTP and I just went in for an oil change and the guy at the dealership told me I had "lower intake and valve cover gaskets leaking" and said it would cost 800. In addition, on my write-up it also said "found oil down back side of oil pan."
#1 Is this the problem associated with the PLASTIC manifold you guys are talking about here?
#2 I can't seem to find anywhere, including here, an answer to this: If they replace the PLASTIC manifold, aren't they just going to put yet another PLASTIC part on, and it'll happen again? If so why would I even bother. Can I get a METAL manifold? Any information would help, thank you!

Matthew Nowlin said...

Jeremy,
Rule #1 in life is don't let the dealership touch your car unless they're working on it under warranty. Dealerships typically charge more than private shops and only have a few experienced mechanics. Why? When you get good at a dealership, you start your own shop.

2 - if you replace this gasket, you should be fine. Realistically a high quality aftermarket gasket will probably outlast the rest of the engine.

BernardL said...

Jeremy,

Matthew makes some good points. Oil leaks on the lower manifold is a common problem on the 3.8L. When they do the repair, the plastic manifold should be replaced too unless it has already been replaced with the updated one. Yes, they will replace it with another plastic manifold but it will be an improved version. The main point to keep in mind is how much oil you actually lose between oil changes. If you're not losing much and you don't want to spend the repair money, check your oil level religiously. The warranty on the repair was for the first five years or 50,000 miles and the class action case is over. I hope this helps.

Bernard

Charlie said...

Hi, I have a 1999 3.8 and replaced the upper manifold and gaskets, but I am still getting coolant in the upper manifold where the manifold meets the throttle body. What else could be wrong? Did I miss something in the R&R? Can the lower manifold cause the issue of coolant in the upper manifold? What other checks can I do to solve the problem. The engine runs great without coolent.

BernardL said...

Charlie, your lower manifold mating surface could be pock marked or warped which would prevent sealing. Did you use GM or Fel-Pro upper manifold gaskets? Is the leak showing up between the upper manifold and throttle body or below the throttle body where the upper and lower manifolds meet? Is the coolant leaking into the engine or out under the throttle body? The gasket may have slipped during installation or proper torque procedure wasn't followed. You may need to take your vehicle to a professional before the engine is ruined due to coolant contamination.

Charlie said...

Hi, I will start from the beginning. The car has 135K on it. The car was given to me to just have after the owner blew the upper intake manifold apart, trying to fuel pressure test it, he said it was surging while idling/running. When I received the car, #3 cylinder only had 30 PSI. I removed all 3 manifolds and replaced the head gasket. That was not the problem, he got a piece of the plastic manifold stuck in the intake valve. Put the head, lower intake manifold and the "used" upper intake manifold the owner gave me, with new gaskets. That's when the car runs fine with no coolant but add coolant, car dies quickly, water out the tail pipe. Coolant in all 6 cylinders and standing coolant in lower intake manifold. Thinking leak between "used" upper manifold and lower manifold, I installed a new upper manifold and gaskets (felpro). Now car runs fine with no coolant but add coolant, it does the same thing, but takes longer. I pressure checked the coolant system while cold and it holds 15 psi, all day long. Also, all cylinders are 160 psi (+/-) 10. To answer your questions, FelPro gasket, leak is not external, can not tell if the leak is between upper/lower manifold but when I take off the throttle body, looks like no signs of coolant loss between throttle body and upper manifold due to plastic not wet. Upper manifold is damp in the curves leading to the intake valves. All 6 plugs are damp. I torqued everything per spec. I could not see any coolant lines (leakage) anywheres around the gaskets, on both manifolds and throttle body. PS: I play with cars just to keep me busy, I mostly rebuild motors for people in my spare time. Took the lower manifold off and going to take it to the machine shop I use to check it. Thanks for listening. Any suggesting would be helpful.

Charlie said...

Also,no pock marks on lower intake manifold, but could be warped..owner stated it never heated up. Can the EGR port in the lower manifold have a crack in it allowing the coolant to go into the port, up the tube and into the upper manifold? I still believe the lower manifold needs to go the shop. Suggestings?

BernardL said...

An explosion severe enough to blow the upper plastic manifold apart could definitely have warped or cracked the lower manifold. When you had the heads off did you send them to a machine shop that pressurizes the heads for cracks? An explosion really opens up the number of unusual causes for a leak like that. The fact it will hold pressure all day cold points to something metallic heating up and expanding thereby leaking through a hairline fracture somewhere. I have replaced uppers and lowers in pairs when I didn't like the looks of the mating surface on the lower. I have not done repairs as yet on one after an explosion in the upper manifold, Charlie.

Mark said...

Experienced the same thing this week. Daughters car has been surging, misfire cylinder 6.. Sunday it just died suddenly. Towed home, pulled upper intake and it is FULL of water. Pull intake, replace plastic gaskets with the new metal ones, fir up - runs good, UNTIL I fill with coolant. Within 3 minutes runs like crap, pull upper intake - full again. I thought head gasket but now I wonder.
Any way to pressure check with upper plenum off?

Hoping...

BernardL said...

You don't mention replacing the upper plastic intake manifold itself, Mark. The main cause of the leak is the upper plastic manifold. The metal gaskets you mention also bother me. I've done a lot of these and neither the OE gasket from GM nor the Fel-Pro one is metal. As I mentioned to Charlie, it is possible for the lower intake surface to be pock marked or uneven. The oil and filter must be changed if coolant contaminated also (I mention this because I shouldn't assume it).

Anonymous said...

Hey Bernard,
I am glad I came across this post.
I just recently bought a vehicle that has a 3.8 V6 With 178000KM. I got a 30 day warrenty with it and on the 30th day the engine blew. I took it in and got it replace and was told that it was the "luck of the draw" When I got the engine changed I was told that they carried over the old intake manifold (Because apparently it was new, replaced the month before I bought the car) The starter, alternator and apparently they put in a brand new water pump and thermo. The new engine had 130000KM. 3 Days later engine blows again. Again, Im told that its the luck of the draw. They carry over all the same parts (starter, alternator, intake manifold (again because its only about 2 months old)water pump, thermo) The new engine now has 119000KM. This time I vow to keep my eye on all the fluid levels. The day I get the car back I notice my oil pressure light coming on and I look at the gauge and its in the red so I take it back the next day and the mechanic tells me that it's fine if it does that while its idling but not while its driving (which it wasnt when it was driving, only at idle) so I checked the oil the second I took my car and it was grey. 1 week later I took it back to the mechanic to do a leak check and I told him about the grey oil and he said its grey because he put in "Lucas"... whatever that is. Apparently there were no leaks, he said it was good to go. I took my car straight to another mechanic and got my oil changed and my rad fluid topped off (because he said it was low) I checked the oil the second I got it out of there and it was a beautiful brown color. Last week I noticed the oil pressure light coming on even while i was driving it so i checked the oil and it was grey again and the rad fluid was low. So i took it back to the mechanic on monday and i was told to bring it in on wednesday to do a "pressure test"... unfortunately the engine didnt make it till wednesday. It blew again. I explained to him what i read in your blog and he said that this 3.8L engines just suck and its just the "luck of the draw" because the intake manifold is new. (The previous owner took the car to him and i figured id go to him with this car since he probably knew the car inside out)I just took the car into him this morning (1 week after itblew) and he said that he's just going to order another engine.
Is it the intake manifold or is it the luck of the draw?
Thanks Bernard.

BernardL said...

What a nightmare, Anon. I don't know what this 'Lucas' is either. If you check the oil filler cap and it has signs of creamy goop, you're getting coolant into the oil. If you click on my blog picture the larger picture will give you a very clear idea of where the coolant's coming from. It could be the lower intake manifold sealing surface may be so pock marked the upper intake won't seal. It may be both manifolds will need to be replaced.

mike.fernelius@yahoo.com said...

how about this one to confuse you I got a 1995 Oldsmobile Delta 88 LSS 3.8L Blew head gasket replaced Head Gasket and plentum. Drove great for 4 days then started it up to hear lifter tick but went away after 2 mins then while i was driving home and oil light came on turned car off and checked oil to find none in pan!!! so left car there and went back in morning and the pan was full???? took back to shop and they started up and oil filter seal blew out as soon as it did the car sounded fine. Replaced oil filter and no noise BUT driving it home after about 20 mins oil light back on and no oil in pan so please if you know whats wrong please let me know 906-440-9154 its one for the books so maybe you have seen this problem before

BernardL said...

Mike,

First off, I hope you had both heads rebuilt and resurfaced at a machine shop. The only thing I can think of causing what you're experiencing is you've somehow partially plugged the oil drain back holes. Either the passages are plugged with debris or you have the gasket partially plugging the holes. The timing case warps and leaks on those too, causing problems with oil pressure. It appears you're going to have to tear it down again, paying close attention to your oil drain back holes.

mike gill said...

this is mike. So your saying i should have my heads rebuilt? could this problem be in fault to the repair shop? they did the work and now im with a dead vehicle what should i do? i work there and i dont want to cause waves but i am out the vehicle. is there a simple resolve to this delemma? the heads are cast iron if that makes a differnece im becoming less and less impressed with the 3.8L youd figure this would have been a simple fix for this vehicle can the head gasket be misplaced in the repair? how much could it cost for the repairs to be done the right way? what did heads cost to be rebuilt?

BernardL said...

No Mike, I'm saying it's impossible for me to advise you on a repair gone wrong. I explained in my last post to you the oil can only be kept away from the oil pan if the drain back holes are somehow plugged or covered. Anytime the heads are taken off of a vehicle they should be serviced in a machine shop and resurfaced. If you feel the job was botched, you'll need to have it taken somewhere else to be checked.

Anonymous said...

Is there a obvious difference on the outside of a updated upper intake, when compared to the original version ?

BernardL said...

No, Anon. The main difference is the metal sleeve they use to protect the EGR passage from burning through into the coolant passage.

Sharon said...

Bernard,

Interesting stuff. I have a 2002 Grand Prix 3.8L(no supercharger)with approx. 65K. Had lots of overheating issues, replaced the radiator first, then finally the upper manifold. A few months later, the oil light came on and I drove it a short distance to the nearest station and filled with less than 2 qts of oil. Drove it for about a month and started hearing ticking sound and had the oil changed. Ended up with bad rod noise almost immediately. I am now looking to replace the engine. Would it help to get a newer year engine or do I just have the manifold work done on an older one. I am looking for an engine with low miles and am in the Bay Area as well if you might know of one or have any advice.

Thanks!

BernardL said...

I'm sorry, Sharon, but I can't even give you a recommendation for a place in the Bay that installs used engines. All the ones who used to be around me are out of business. That will be your main problem. As to used engines, you might want to click on Matthew Nowlin's name in the comments section. He's a reputable used engine seller in the Boston area. He may have connections out here in the West. I'm sorry I can't advise you further.

Sharon said...

Thanks, Bernard. Do you have any thoughts on the newer model engine question? Is it even an option to go to a 2006 or newer?

Matthew Nowlin said...

Sharon, it is a no go on the '06 3.8's for you. GM used essentially the same engine from 1995-2005. Despite your experiences, and despite this line of discussion, it is normally a rock solid engine. Though folks like Bernard and myself deal with the issue you are having on a regular basis, the truth is there are millions of these engines on the road - probably more than 20 million - and we deal only with problem vehicles!

I'm sure no one ever brings Bernard a car that doesn't have a problem!

So while this is definately a problem, the great majority of folks with this engine will never have to deal with it.

I don't like to sell these engines because, despite what I just said, I hate them and don't buy many of them any more unless they have super low miles... so I'll give you a phone number of a west coast company that has always done a good job for me.

Call 800-444-4344 and ask for Dean. They should be able to ship your engine to the bay area. Keep in mind that everyone's standard warranty on a used engine is a part, no labor warranty. Most reputable places have a labor warranty that you can purchase at an additional cost. The name of the company is Gundies and I consider them to be one of the premier auto dismantlers on the west coast.

I find California and Texas salvage yards have gone down hill in the last five years, mostly because Mexican drug cartels are buying many of them to launder drug money. Sadly, this is not a joke. Many reputable salvage yards have gone out of business because they can't compete price wise with a salvage yard that exists to hide money with volume sales and who don't care if their "business" makes or loses money!

Hope that helps you!

BernardL said...

Thanks for the help, Matthew.

I don't do any used engine work, Sharon. Give the yard Matthew noted. They'll have the info on whether you can do it or not. I'm sorry yours failed. I know how costly even having a used engine installed is nowadays.

Kevin E said...

I just had my intake on my 2001 impala explode and catch fire. It got put out right away. Have you heard of this problem and if it did it once will or could this happen again. The car has 180,000 miles on it

Matthew Nowlin said...

Kevin,
In my experience this is not a common problem by any means. The thing about burned engines (I see them in the computer all the time across the US at various salvage yards) is that they come across all makes and models. And as far as Series II 3800's go, I don't remember seeing too many burns.

Bernard might have different experiences though. I'll be curious to see what he says.

BernardL said...

As Matthew said it's not a common problem, Kevin. Extreme Backfires in the intake from misfiring cylinders, jumped timing, fuel leaks can cause explosions. The Exhaust Gas Recirculation tube may have burned through more than just the coolant passage in the upper intake. With a 180,000 miles and an explosion you'll be gambling with patch repairs. A professional inspection is a must before you go any further and may require an engine tear down. If your Impala is not in almost showroom condition otherwise and the transmission also has 180,000 on it without any repair, it may be time to cut your losses - depending on what a professional tech finds out during the inspection.

Anonymous said...

If one of these manifolds fail and you have lifter noise when you first start the engine, do you have to replace the lifters when you replace the manifold?

BernardL said...

Anon, the lifters making noise is usually the first sign of coolant getting into the oil. Check the oil filler cap. If it has a creamy substance on the underside, coolant is definitely getting into the oil. The procedure after that is to replace the upper plastic manifold, flush the oil and goop out and change the filter. I use Motorcraft Synthetic Blend Oil at my shop. Then change the oil and filter again in 500 miles and every 2500 miles after that because the coolant in the oil would have done some damage. If the lifter noise dissipates, then great. If it doesn't, then you have bigger problems than just the lifters.

Bill Fitzgerald said...

I bought a 2001 LeSabre about 2 1/2 years ago. It had only 41000 miles, so I thought it would have a good long life.
About a year later, I realized that I was having to add coolant regularly and took it to the Buick dealer who assured me it was normal to have to add a pint of coolant between oil changes! There ws no sign of coolant in the oil, though, no milky residue.
I began to hear the lifter noises and took it back to the dealer who then changed one of the gaskets (not sure which one). Three months went by and I noticed the coolant was low again. Took it back and they replaced the other gasket. Great - no more coolant loss.

Last week (about a year later) on the way back from a Florida vacation the car began to lose power and made a horrendous metal-to-metal hammering. Of couse, the engine had failed catastrophically and of couse, about 500 miles from home. The only option was to take it to the local Buick dealer.

I'm am trying to work with Buick to offset some of the cost ($3800 for a USED engine). I'm guessing it's a lost cause given the financial trouble they're in (I wonder why).

Any suggestions?

BernardL said...

I'm sorry, Bill, but it seems the coolant mixed up with the oil for too long a time. The dead giveaway on those is if the creamy substance shows up on the underside of the oil filler cap.

I don't see how you can get anything from the dealer or GM. You're the second or so owner. The 3.8L is not a bad engine except for that plastic manifold which you didn't say whether they replaced or not. My guideline for vehicles in need of very expensive repairs - if you can't sell it for more than the price of the repair the day after you get it fixed then I recommend against repairing the car. I wish I had better news for you.

Matthew Nowlin said...

I sell used engines. You should be able to get a good used engine for that for no more than 12-1400, shipped, and have a private shop install it. Good honest florida shops charge 800-1200 for something like that.

I can recommend Ole South Auto Salvage, in Venus, Florida. Ask for Chip or Dale.

Also, buy a CARFAX account to run the vin off the vehicle the engine is coming from before they ship it, to make sure no one did an odometer rollback before they bought the account.

Matthew Nowlin said...

Oh, and I bet the dealership never said anything about the miles on the engine they're selling you.

Sadly, that's why many are scared of used engines.

BernardL said...

Thanks for giving Bill the recommendation, Matthew.

Bill Fitzgerald said...

Thanks, guys. Too bad I was stranded so far from home where the only option that I knew of was the local Buick dealer (ouch!). I have the car back now and guess what - about an hour on the road and I began to smell a heavy coolant odor. Couldn't see any leaks, but the coolant is going somewhere because the reservoir is low now. And, yes, I had the intake manifold changed about a year ago on the old engine ($500 down the toilet, I guess). Never did see any "cremy white stuff" on the filler cap, nor any discoloration in the engine oil.
And for Matthew - actually they told me that the engine had 60K miles on it. Getting the VIN would have been a great idea, but I guess it's too late now. I'll ask anyway.

Anonymous said...

Bernard, The little stove pipe that comes up from the lower manifold and into the upper manifold, what does it do? Water does not come in through that little pipe, does it? The reason I'm asking is because that little pipe is just upen at the top, so if water comes through it, it would be just runnning out the top like a fountain.
So, when one of these goes bad, where or how does the water enter into the upper manifold????
I'm repairing my 3rd one, this time on a 2000 Park Avenue. Other than the water in their, I see no hole or damage and didn't on the last one either. I replace the upper on the last on, a pontiac, and it worked fine after that,so expect this one to be the same. But it boggles my mind not understanding where the water comes from and/or how that egr pipe causes it, especially when there is no cracks or holes.
Can you explain, please.

BernardL said...

Anon, if you click on my post pictures you'll get a much enlarged view where you can see the hole burned through because of exposure to hot combustion exhaust from the EGR (Exhaust Gas Recirculation) passage. The passage allows a metered flow of exhaust air to be used in cooling down combustion temperatures and lowering Nitrous Oxide emissions. The new upper intake utilizes a metal tube to shield the plastic manifold from exposure to the EGR passage gases.

Anonymous said...

Hoping you or someone has an answer for my 3.8 Buick problem. This is my wife's car and she has only had it a year. It is a 1995 LeSabre that began to have low oil pressure and a noisy lifter(s). We desided to have the motor rebuilt by the local NAPA machine shop who also installed a re-ground cam as one lobe was shot. An oil pump kit was also installed that solved that problem. We had a mechanic friend remove the engine and install the short block. He reinstalled the rest of the motor without any problems. The engine smoked steady from the first drive home and after only about 700 km (500 miles) we have gone thru nearly 4 litres of oil. There is no visible leaks and upon removal of all plugs we found #2 cylinder's plug competely fouled. The guys at NAPA removed the rear valve cover to check if the valve seals were there and confirmed that they were. There has been a lot of talk about intake manifold problems and I'm trying to get to the bottom of this issue. #2 cylinder has 180 psi as compared to one from the front having 170 psi. Could they have left off the oil ring or could the oil be sucked into the cylinder from the top of the motor? A bore scope view showed no scores and the piston looked fine.

BernardL said...

I'm sorry, Anon, but after a compression check is done taking apart the engine is probably the only way to find out what's happening with your oil loss. It's obvious you're burning oil in #2 cylinder. It has to be coming up from the rings, going down through the valve stem, or being drawn in from the intake manifold.

Anonymous said...

Thank you for your prompt reply Bernard. One comment I forgot to add was that I was informed by the NAPA machinist that my wife's engine required gaskets which were specific to only that year of production (1995) VIN# 1G4HR52L4SH495851 and they had some problems finding a set.

If I understand correctly when looking at your photos of the composite intake there are two holes (orange circumfrance) beside the EGR port/throttle body end in which coolant passes through. Burning back of the plastic EGR port into these coolant holes allows the coolant to enter the intake end of the throttle body. And that this is the only section of the lower and upper intake manifold that coolant passes through.

From the Sept 01/09 blog "Matthew makes some good points. Oil leaks on the lower manifold is a common problem on the 3.8L."

Bernard I think I will have my mechanic friend check this out as the new valve seals are there and I honestly can't see the shop failing to notice they missed installing one oil ring.

Matthew Nowlin said...

You're also dealing with an engine that remanufacturers on professional lines are having more and more problems getting right. The reason?

Pitting around the intake ports from really old coolant eating things. GM coolant - the long life stuff - uses an organic anti-corrosion chemical that can last at most five years. After that point, it goes to work.

If that hasn't been at a minimum resurfaced (or at a maximum, built up and then resurfaced) it might be impossible to get that seal you need to prevent oil from dumping in.

The real question I have is why NAPA did extensive head work AND put a new short block in. That sounds to me like an example of the phrase "When you have a hammer, every problem becomes a nail." In this case its "When you run a machine shop, every engine problem requires a rebuild."

The truth is 3800's are super common and unless you got a brother in law deal, you would have been much cheaper to put in a reman - which NAPA has great prices on, btw.

What did they charge you?

Oh, and are they using Felpro gaskets?

Anonymous said...

Matthew, due to not knowing the history of the car, the low oil pressure, and increasing top end noise which was resolved (for only a very short time) after replacing a lifter (which was so bad that the roller cage was broken and missing all of the bearings) we desided to have the engine rebuilt. We had no idea what else had been damaged due to the low oil pressure issue and felt that this was the best route to take. After we explaned the issuses to the NAPA machinist we were quoted $2200 + taxes for the rebuild and told there might be an additional charge of $150 + shipping if we required a reground cam. After the engine was ready they called and told us that there was an additional charge because they had to install a rebuild kit into the oil pump. When I went to pick up the motor the bill had jumped to $2800 + tax. The cam was $150 + $25 shipping, the oil pump kit was $139.00 and the rest I was told was due to them having to buy the gaskets from a supplier that they normally don't deal with. There regular supplier did not have the gaskets and told them the set was unique to the 1995 engine only. I can tell you we were not impressed! Who quotes an engine rebuild without including the oil pump (which is the heart of the motor)??? AND who quotes a cost (not a ball park cost) and feels justifed to increase the final cost due to an internal gasket supply problem? The did use Felpro gaskets. And after some talk with the machinist and manager we were offered a refund of $150 + tax. This all they would do for us and we were told we had nothing in writing (neither the $2200 quote or what was included in the rebuild cost). We took the refund and will get everything in writing next time.

Was I correct about my understanding and comments on your intake photos?

BernardL said...

You're right on a few points, Anon. I've never dealt with a rebuilder who didn't include the oil pump on an engine job. It's illegal here in California to not put the estimate in writing. It's also illegal to increase the estimate without an okay from the customer in person or by phone (all noted, including time called and initials of person spoken to). Yes, the EGR passage is the only place that burns through into a coolant passage. As Matt pointed out the lower manifold can be pitted because of coolant deterioration.

Now, returning to your problem. You're fouling out #2 spark plug. An oil leak on the outside of the intake manifold will not foul out the #2 spark plug. Oil can be leaking from the intake due to a misplaced gasket or an incorrect one. As in my earlier post, the only way I see to find out what's wrong is starting at the top end and taking the engine apart. Forget the price. You've paid it. Now, Napa should stand behind their work and fix the problem.

Anonymous said...

BernardL, do you think that it is possible for that much oil to be sucked into #2 from under the intake manifold gasket? The manifold was removed and replaced by the same mechanic when we originally found the lifter problem (without any fouling problems and driven for 1000 km before we had the latest work done) and new gaskets were used ( I believe that they were FEL PRO). The same plugs had no abnormal signs at all.

ALSO I know there is a specific torque of 136inlbs as well as a specific torque sequence. Apparently according to NAPA the back and front gaskets are the same shape just reversed (not interchangeable) and there is a "top" and/or "bottom" indicated on them.

I checked with an online auto parts store (Northern) and checked their listings for the 94, 95 and 96 3.8 gaskets. I do not know why the full engine set for the 94 (FM Gaskets 260-1566) is different than the 95's (FM Gaskets 260-1740) but they list the same FEL PRO lower intake gasket MS94918-1 for both the 94 and 95 applications. I also noted that the 96 lower intake gasket listing states "with locating pins" FEL PRO MS98014T . I wonder if the wrong gaskets were ordered and will check with NAPA as to what they included in the gaskets they gave me. Perhaps they have the holes for the 96 locating pins?


Tomorrow my mechanic and I are going to remove the injector runner and have the NAPA machinist come down with his bore scope to look into the #2 injector/intake valve port.

AND on monday I am going to check with the local dealership to see if the upper upper plenum was upgraded due to the recall. I'd hate to see all of this money and work go down the drain due to its failure. The car has 258,000 km.

I have read that Dorman Industries (USA?) makes the updated upper plenum. Do you know what the correct part # is for the 95 replacement? Or do you reccommend a different aftermarket or GM replacement? Thanks to you and Mathew for your replies and info!

BernardL said...

It is possible for a very large amount of oil to get into only one cylinder through the intake due to misplaced or wrong gasket. I don't know the part number for aftermarket parts on the 3.8L. Except for Fel Pro gaskets, I use only OEM parts when replacing either the upper plenum or lower intake. I can't tell you much about the before and after of your repair work other than when a spark plug is awash in oil it's usually coming from the bottom unless a gasket on top is allowing a direct leak into the cylinder.

I hope the bore scope reveals the problem but my guess is there's something wrong in the rebuild due to clearances in #2 cylinder. I wish for your sake it's the intake gasket misplaced.

Anonymous said...

Thanks again for your prompt reply BernardL. When we removed the fuel injection runner the bore scope really didn't reveal any obvious differences from #2 hole to the rest. But using a long drink straw we were able to wet it in #2 with about 1/16-1/8" of oil. The next step is to see if there is any damage to the intake gasket(s) due to possible over torquing (the NAPA machinist tells me they are easily cracked as they are plastic). I have checked with the local dealership and by tracing the VIN # (L series) they state no recalls are shown in their GM computer system. I have looked and found four aftermarket manufactures of new phlenums and they are DORMAN 615-179, DEPHI W0133-160, A1CARDONE A187160 and ATP 106001. Do you guys know of any other brands? Who recommends what brand? The dorman is advetised as a kit which contains all that is required to complete the R&R job.

Matthew Nowlin said...

The NAPA technician is wrong. The gasket does not use plastic, it uses Nylon. :|

BernardL said...

I didn't think you'd find out much without tearing it down further. I can't advise you on aftermarket manifolds because I don't use them. The top priority is finding out why #2 cyl spark plug is awash in oil. Concentrate on that first.

Anonymous said...

BernardL, the teardown begins... Intake manifold off..
1) no broken or visably damaged gasket(s) and are correct application
2) removed upper plenum and found some old oil residue in it and on the PC valve? ... as there are no oil gallaries in the intake manifold must be due to accumilation from previous crankcase gases? (no other spark plugs fouled or oilly)
3) No visable cracks or defects in the lower intake manifold.

BernardL said...

I'm sorry, Anon, but I can't think of anything other than a error in the lower end rebuilding process concerning #2 cylinder if everything was okay on top. From your description before with #2 awash in oil, that usually means it's coming from below.

kurbs said...

The problem with plastic intake manifold gaskets also exists on engines other than the 3.8. I just had the gaskets on my 2003 S-10 with 4.3L replaced. I first noticed that the level in my coolant reservoir was always getting low. Searching for an external leak, I noticed that a nickel sized spot of coolant kept appearing on the front of the engine on the pad where the timing cover mounts. I thought it might be from the thermostat, but it was dry. Radiator was ok, hoses ok, freeze plugs ok, water pump ok, etc. There was no evidence of oil in the coolant, or coolant in the oil. Recently, while changing the oil, I noticed coolant dripping down the back of the engine along the trans/engine mating line. I traced the coolant back up top and noticed wetness along the intake/cylinder head mating area. Right then I suspected the intake gaskets. Not having enough time to do the job myself, I took it to the dealer and got soaked for close to $1,000. The original gaskets were plastic and had degraded around the coolant passages on both sides. The new gaskets are metal with a silicon bead. Will this solve the problem once and for all? Even though it was only two days between changing the oil and the repair, should I change the oil and filter again? I also have a problem with way the bolts are not perpendicular to the sealing surface, like on the original small blocks. Is this contributing to the problem? I've heard that the bolts were over-torqued at the factory. What is the proper torque when using the new metal gasket?

BernardL said...

I never claimed the 3.8L was the only engine having intake problems, Kurbs. They're the most notorious. As Matthew pointed out in an earlier comment the gaskets are nylon.

'The new gaskets are metal with a silicon bead. Will this solve the problem once and for all?'

Probably, but it's impossible for me to say. I haven't had any returns and I've been changing them since the problems first started showing in the nineties. I use Fel Pro Gaskets though.

'Even though it was only two days between changing the oil and the repair, should I change the oil and filter again?'

In your case it seems the leakage was external rather than internal. If there was a creamy substance on the inside of your oil filler cap then the leak would have been internal.

'I also have a problem with way the bolts are not perpendicular to the sealing surface, like on the original small blocks. Is this contributing to the problem? I've heard that the bolts were over-torqued at the factory. What is the proper torque when using the new metal gasket?'

I doubt it because the replacement gaskets last indefinitely. I have no idea if they were over-torqued at the factory. My guess would be no because of the precision procedure they have in place.

Anonymous said...

Thank you Bernard for all this info on the 3800. I had white smoke out of exaust, replace all gaskets for manifold and cylinder heads, did not fix the problem. I was about to junk the car until i came across your blog, there was a crack on the upper intake manifold.
thanks again
Jay

BernardL said...

That's really good news, Jay. Thanks for sharing it. Change the oil and filter at 500 mile intervals the next couple times to make sure you get all the residue out of the lower end.

Anonymous said...

BernardL, the teardown continues...

4) rear head removed no visible damage to #2 cylinder or head gasket

5) one dime sized carbon deposite noted on adjacent piston's (middle piston) face (no fouling of plug)

6) oil pan removed and #2 piston removed.... confirmed all rings had been installed

7) upon closer examination by NAPA machinist (his assistant assembled the short block motor) he notes a problem with the three piece oil ring... "I can see that the wrong oil ring was installed ... the package must have been previously opened and an incorrect one mixed in."

8) I was told he would get the proper ring and this would solve the problem. When I suggested we remove the other two rear pistons to confirm everything was "A OK" he stated "they have to be correct since those plugs show no signs of oil." I pressured him further and he aggreed it would be wise to confirm this since it would only take a little more time.

9) same problem wrong oil rings!

10) front head removed and front three pistons removed...again wrong oil rings (apparently application is for the 1996 Buick 3.8)

11) one two inch sized carbon deposite noted on one of the front cylinder piston's face

12) NAPA is taking responsibility for replacing the neccessary gaskets oil rings, shop supplies and labour, but my mechanic and I are still scratching our heads as to why the other cylinders do not show fouling of the plugs. My wife and I are insisting NAPA measure and confirm everything prior to our mechanic and the NAPA machinist reinstalling everything.

Still scratching my head!!! And looking for addvice too.

BernardL said...

The only advice I can give you is make Napa fix it since they caused the problem. I'm sorry it turned out for you like that, Anon.

Anonymous said...

BernardL: What can cause coolant to sit on top of the lower intake 3800 series ii engine. I did replace the upper intake manifold and still coolant is mixing with the engine oil. Can the coolant make it to the top of the lower intake from a crack engine block or crack cylinder head?
thanks
Andy

BernardL said...

Andy, did you replace the upper intake with a new OEM one from the dealer? If there is still coolant on the top of the lower intake the most likely cause is the upper intake still leaking or the gaskets not positioned properly. If the lower intake cracks it either deposits coolant into the oil or the combustion chambers because vacuum pulls the coolant away. The upper intake leaks onto the top of the lower manifold because it seeps through under pressure from the coolant passage near the EGR tube - where it burns through as in my post's pictures.

Anonymous said...

BernardL: I did use the new Dorman Upper Intake Manifold it came with a gasket, the only thing i could think of I did wrong Is I tighten the bolts too much. I will check it later today to see if there any damage to the gasket to confirm.
Thanks Again
Andy

Anonymous said...

BernardL: I dont't no if this is good news, I just took off the new upper Intake Manifold, no coolant in sight.I guess the manifold took care of the leak up top but I dont know if it too late to save the engine. I remember taking off the cylinder heads a few weeks back and the rods on the cylinder closer to the winshield were a charcoal color. My wife did drive a few miles when the car was white smoking in exaust. Could it be the cylinder head is crack, I did not notice the heads were warp when I check or could it be the Engine block.
thanks
Andy

BernardL said...

Andy, I know this advise comes too late, but ANY time you take the heads off any vehicle with overheating problems take them to a reputable machine shop and have them gone through completely including hydro-testing. Yes, anything could have happened, including cracked heads, block, etc. Usually the head gaskets are good indicators if they show excessive heat damage.

If you get it back together now with no leaks, the only thing you can do is keep a close eye on it and don't go on any out of town trips.

Anonymous said...

BernardL: The car is not drivable, I just drain the oil, alot of coolant in the oil. Do you recommend I change the cylinder head? What are the chances its the engine block? I took the upper manifold off, its dry no coolant in sight. But, I fill the radiator up with coolant and I can see the coolant in the holes next to the egr pipe. If the engine block was crack wont the coolant drain out with the engine off? Or does it have to be pressurize?
Andy

BernardL said...

Andy, from the way you've described your problem, you're in over your head. I can't diagnose your vehicle from here. I think you need to find a professional repair shop. Before you do that though it is time to consider a reality check. Is the car in showroom condition? Do you like the vehicle enough to pour thousands more dollars into it? If the answer is no to either of those questions - scrap the car and cut your losses.

Yes, the system must be pressurized to reveal a leak and if either the heads or block are cracked and leaking internally you won't be able to see exactly where. In a professional shop, head or block cracks usually result in a complete engine replacement because gambling on patch repairs is BAD business.

Anonymous said...

BernardL: Thank you for your advice, I guess I will be getting the new Ford Mustang after all. Too bad about this intrigue, i just replace the compressor, tires and tried all these repair on the engine. The intrigue gave me over 300,000 miles, too bad a stupid cracked Intake manifold cause all these problems.
thanks again
Andy

BernardL said...

It is a shame, Andy. I hope you can get something for the car from a scrapper.

Anonymous said...

Hello Bernard

I got that Mustang I told you about last week, 2007 model.Wow what an awesome car from Ford. I will try to fix the intrigue anyway. I got a quick question for you. The new upper Manifold took care of the leak up top, but coolant is still getting in the oil. I too the upper off, then the lower manifold off. Coolant is present under the lower manifold. what can be the cause of this? I know I can see the cylinder head gasket on both sides, those r new. Can a crack cylinder head leak coolant under the lower intake. Also if the block was crack, I don't believe coolant will end up in this area. Please let me know, I am trying to fix this car for my son he just turn sixteen.
Thanks
Andy

BernardL said...

Andy, it could be a warped intake manifold surface, pock marked mating surface, cracked heads, misplaced gaskets, and even a cracked block as you asked about before. I'm still confused why you've not made the machine shop repair what they obviously screwed up to begin with. You have to understand this - there's no way I can tell you what's causing your coolant leakage from here or even point you in the right direction other than to reiterate what I've already told you about the importance of hydrostatic testing of suspected parts by the shop that rebuilds an engine - during the rebuilding process. When the block, heads, and manifolds are not thoroughly inspected during the rebuilding process, therein lies disaster.

Anonymous said...

BernardL: What is the going rate to have the test done by the shop, this way I dont get ripped off.
Thanks again
Andy

BernardL said...

I have no idea, Andy, and frankly, I don't think you've thought this through. Your best bet after having the last rebuilder screw up is to make them replace your engine with a quality rebuild or else dump the car.

sportfury1965 said...

Where can a new upper mnaifold be obtained?

BernardL said...

I buy the OEM replacement manifold from the dealer, sportfury. As one of the other comments mentioned some aftermarket manifolds are offered, but I only buy OEM for my customer's jobs.

Anonymous said...

BERNARD/ I HAVE A 1995 BONNEVILLE SSE AND MY PLASTIC INTAKE BLEW UP IN 10 DIFF PARTS Q: CAN I JUST PUT A NEW ONE ON AND IT BE OK TO GO?

BernardL said...

Anon, until you know exactly why the upper manifold blew up, the answer is no. If you find out it was because exhaust gas built up in the wrong places due to leaking through that EGR passage in the upper manifold rather than leaking fuel injectors, I would still replace the lower intake manifold too. Another question is whether you have coolant mixed in with the oil already. If so, everything you do will be a gamble.

Anonymous said...

my 98 buick park ave. 3.8 blew the upper manifold apart during cold start. as i am selling now, would new upper manifold and map sensor fix it or is something else wrong?

BernardL said...

You'll need to find out what caused it to blow apart first, anon. Any damage done to the wiring harness, injectors, and lower manifold will have to be examined too. Last but not least, a compression check should also be done. I don't know how much you'll want to spend on a car you're selling. The repair cost will probably be up at the amount you'll be able to sell it for even if the repair is successful.

e_bayd2deth said...

Hi, I was reading through your previous postings over the last few years. I just picked up a 97 Park Ave for my wife to commute with. It had burned hole in the stock upper intake facing the throttle body. Luckily I was able to find a new updated upper intake with the replacement egr tube. Here is the problem I am having. The car starts up and runs great. About the time the car gets to approx 190-200 degrees it starts dumping coolant into cylinder 5. About the time the thermostat opens. I did a compression test on 3 and 5 and both were holding around 160lbs. I checked the lower intake twice to make sure it was level and smooth before installing the upper intake. I also heard that the lower intakes are usually good and do not leak.

Any ideas to why its leaking into cylinder 5 only? Thanks!!

BernardL said...

My best guess e_bayd is a cracked head or block if you see no indication of the upper still filling the intake tunnel with coolant. It may be the prior owner had the problem for a while and overheated it. Tear down may be the only way to find out. After taking the heads off and having them hydro-pressure tested, if they test well it would point to a cracked block.

This all hinges on whether you examined the lower intake sufficiently and did the upper intake correctly. You're wrong about the lower manifold. They do leak and could very well be leaking into #5 cylinder.

If you don't want to spend anymore time and money on the car you could try using a sealer like Bar's Leak Sealant. Your wife will not be happy if she gets stuck in commute traffic though. I'm afraid your only options are expensive ones if it's not the lower manifold.

e_bayd2deth said...

Bernard,

You can see evidence of coolant in the lower intake port of cylinder 5. Even after the upper intake has been changed out. The local GM dealership is the one who told me that the head gaskets and lower intake manifolds rarely have issues. I am going to pull both intakes today and and do an inspection. Is it possible for the car to run fine with a cracked head or block until it heats up? The previous owners swear it started doing this one morning.
I will let you know my findings...

Thanks

BernardL said...

It is possible for the car to run fine until heat builds up in the combustion chamber if the head gasket, head, or block has a hairline crack. Be very careful pulling off the lower intake so you may be able to spot a break in the gasket not caused by you removing the manifold or corrosion near the water passage. Good luck.

The Machiavellian said...

just came across your blog. Of course I was researching the 3.8 V-6 plastic manifold issue.

My 2000 Buick LeSabre with only 48,000 miles has this problem.

Last week, the heat would fade in and out as I drove.

Took it to my mechanic and it is the plastic manifold issue.

Luckily, no cracked block as I guess I caught it early enough.

Still, it is a very expensive surprise on an otherwise no problem car.

BernardL said...

I'm glad you didn't have a major engine problem because of it, Mach. Keep an eye on the underside of your oil filler cap and make sure the telltale creamy residue doesn't show up on it. Thanks for posting.

Anonymous said...

Bernard,

Great site. I discovered it by accident sometime back and I enjoy your political comentary. You should take an Op ed position at the NYT(oh wait you have the wrong political leanings)

Anywho I just changed the upper and lower manifold gaskets on my
3.8 (Lesabre), the manifold was upgraded 8 years ago(when the engine was replaced) and it was still in good shape. In fact this car has been reliable transportation for over a decade.


After completion I started it and it was idleing pretty rough. I started digging for the spark plug wrench (to check for fouling) and realized I had left a piece out of the upper gasket. It's an amber(maybe oil stained) 3/8" x app. 10" plastic tube that lays legnth-wis across the plenum gasket. My gasket kit didn't come with it so I had forgotten about the piece.

My questions are:

What is this called?
Where do the ends connect(no mention in the manual)?
Have I done damage to my car by starting up without this piece?
(I only started twice for less than 30 seconds)

Thanks in advance.

BernardL said...

Anon, my advice is to redo the job using a full gasket set from the dealer or Fel-Pro with a detailed manual with diagrams. I always advise taking digital pictures as you go along but that advise is a little late for you. Don't worry about the names. Just redo the job correctly. You won't know about damage or anything else until you have it running again. If you have any question as to whether you can redo the job correctly take it to a professional now rather than risk damage.

HughW said...

Thanks for the great site Bernard. I've just performed the replacement of the UIM and LIM and took advantage of open space to replace valve cover gaskets too. I'm a shade-tree-mechanic (STM) so work slow and tried to take lots of pictures. But alas missed some. I need a vacuum hose layout picture. Almost all the vacuum hoses were shot. I replaced most of them but I have a check value still needing to be installed.

I'm still searching for a great 8 part video that led me by the hand in this repair. I might be able to see my hookups if I find that again.

Just one other point. Its rarely mentioned that the injectors are removed and thus need to have new O rings. This STM understood the need but not the difficulty. The nifty tool for stretching the O ring so it slips nicely over the lower tip without damamging the injector was rediculous/impossible to use. So I manufactured an O ring stretcher and installation tool. Other STM's may want to try this. I used two 3" long 1/4" socket drive extenders. First was wrapped with tape for snug fit and slipped through the supplied nifty tool. The second was attached to the first. To use: Slide the O ring onto the second's 1/4" square end and roll until it is stretched over the drive body. Keep rolling until its rolled on to the nifty tool. Remove tool and insert over tip of injector. Roll the O ring off onto the injector. Time: 2 hours of design, 5 min to build, 3 minutes for 5 injectors. First one was for practice and training.

BernardL said...

I'm glad it worked out for you, Hugh, and yes marking vacuum line positions if you are unfamiliar with a job is very important.

Anonymous said...

I got a 3.8 L GM with the black plastic manifold.
Not sure what car it came out of because it's a replacement engine with the bar code on the front valve cover.
How can I know if this engine's upper intake is the new revised upper intake manifold so I won't be wasting time and money on a new one ?

Anonymous said...

Hi Bernard

I had or have a Chevy Lumina 3.1 with the intake manifold problems and 2 times I ran it with coffee , that's what it looks like after the oil and water mix.
I guess I got very fortunate because this happen 2 times, first time Firestone drained the oil and then ran some trans fluid in it and then drain that and put oil back in.
The 2nd time it happen I pulled the intake and all the lifters, robs, can were caked in the creamy oil water mixed goop.
I cleaned it all and put a new gasket on it and put it all back together and it's still running.
By the way ? this engine also has over heated on me 2 times.
Not only check the oil cap but, if people are concerned that their engine is one of the less fortunate one's with these gasket and intake problems, check the dip stick every time you drive the car until you can get it fixed.
Coolant in engine oil looks like coffee.

BernardL said...

Anon, there's no way to tell with it on the engine. The revised manifold has a reinforced EGR passage where the old ones burned through. Click on the pictures of this post to enlarge them. If the manifold you have is just plastic in the spot like the picture then you have the old type.

Anon, yes, mocha on the oil cap is trouble. On the 3.1 you have head problems, with the overheating you're getting. You'll need to have it torn down for repair or if the car's not worth it, you can try a sealer like Bar's Leak.

Anonymous said...

Hi Bernard, no more over heating on the 3.1 , just the fan does not run when it's suppose to.
The engine is still running great after 2 over heatings and coffee cafe oil.
I got a 3.8 L no, yes, I will check the plastic on the intake.
The dealer told me the engine that was put in this car only ? has 26,000 miles on it and has a bar code sticker on the front valve cover that my brother told me that it's a GM replacement engine.
If I take the intake off, what should I look for at the lower part of the intake, pitting ?
I hope I don't have to buy the lower part of the intake also.
I know what your going to ask, am I getting coolant in the engine on the 3.8L ? , and the answer is no.
This is a pre caution measure so the engine does not get messed up.
By the way ? the mechanic who the dealer had put the engine in this car may have put the throttle body on crooked because there looks like a gap between the throttle body and intake.
I never took a 3.8 L upper intake apart before, is that gasket reusable ? what should I look for when I take it off ? will there be coolant coming out and will it go into the engine ?
By the way ? the intake on the 3.1 L ? NO FUN, I did 2 of them and the first one was on a van with no room behind the engine.

BernardL said...

Anon, you ignored my answer about clicking on the pictures of this post to enlarge them. I can't explain better than the actual pictures I've already placed here. If the engine only has 26,000 miles, it's probably never had the plastic intake replaced. As to how, you must get a manual, preferably a shop manual, and follow the directions exactly.

Anonymous said...

hello BernardL,
my 03 gp 3.8 has a leak, thought it was intake but it looks like its coming from the passenger side black tube coming from lower intake into or towards heater core, can this be a easy fix? thanks, bill

BernardL said...

Bill, I'm not from the shorthand, texting generation. I need a heck of a lot more than what you gave me to even make an intelligent guess. If you take it into a shop they will pressure test the system and be able to tell you exactly where your leak is.

Anonymous said...

My 1997 Buick LeSabre is in the shop right now for this very problem. Its got 120,000 miles and started running rough and slightly hotter than normal, so I flushed the coolant side, new Thermostat, new oil & filter and replaced the plugs. Well, on the test drive it quit all together. Got it towed home and found the telltale milky oil under the fill cap and thought "Head Gaskets"! Pulled all the plugs and barred it over by hand and coolant shot out of #2 & #5 cylinders. That's when my local mechanic guy told me about this plastic intake problem with the 3.8L engines. He's fixing it right now and told me I was lucky and caught it before I destroyed the bearings or worse, hydraulicly locked the engine! I should be driving it home tomorrow!

BernardL said...

I hope your mechanic friend is right, Anon. In my experience when they lock up on the freeway, they're toast. Listen for lifter noise if you get it back running, especially in the mornings on a cold start. If they clatter longer than a few seconds, it means oil pressure is taking longer to build up because of excessive clearance somewhere in the lower end. If everything seems fine. Change the oil and filter again in five hundred miles, and every thousand for a couple times after that. I am assuming your friend will be flushing it out and changing the filter after the repair. Good luck.

Anonymous said...

hello BernardL this is Bill from the shorthand texting generation on the 3.8 L GP that had a lower intake bypass tube rot out, I did fix it myself and was pleased to find how easy this was, about an hour and half, remove overflow, bely, alt and 3 bolts for tensioner assembly and pull , wa laa, remove broken pieces of old tube, lube lightly and reassemble, bill
l

BernardL said...

thks 4 update, bill. :)

Anonymous said...

i have a 2004 grand prix, with the na 3.8 series 2... the car was running warmer than usual, but we had a very hot summer... i changed out the thermostat, and the temp was a little cooler... but still hotter than normal... one day driving home my temp gauge started climbing, and the car shut down the a/c to protect the engine... i tried the heater, to to cool it off... no heat... i thought it was the heater core, but the mechanic i called said it was probably the upper intake... there is also a elbow tube, at the pulley side of the motor that is puking coolant... but no coolant in the oil, and the car is a quart low... does this sound right fore this issue??? he said with no surprises, it will run me $500-$600 to fix... can i do this fix cheaper myself, what tools will i need, and where do i get the 2 pieces of plastic???

BernardL said...

Yes, Anon, it seems you have an intake problem. Also the cooling fans should be checked for proper operation. As to whether you can do it, how can I know the answer to that? If you do attempt it get the shop manual for your vehicle. Helm Incorporated sells the OEM manuals on line.

Anonymous said...

I hate to read all of these comments about the 3800 with the P.I.M. I found this thread because I have a close friend, whose son has a Monte Carlo of the early 2000's and it may just have this problem. I was hoping that Gm was still willing to "do something about their "screw-up", but I guess not.

What REALLY bothers me...Is that I own an '89 Olds Trofeo, with the SAME engine, minus the PIM. It is a GREAT engine!! And a great car too. Probably a decade ahead of its time or more. It is VERY reliable--MUCH more than many cars, 5, 10, even 15 YEARS newer!! The engine uses MAYBE .5 qt of oil/4k miles, starts in ONE second--even if it is cold outside-- and runs VERY well, with decent power and mileage!!It gets driven about 70 mi EVERY day.

So..just WHY, did Gm take a VERY nice engine like mine, and in 1994, RUIN it with the PIM?? The 3800 --WITHOUT the PIM--!!-is one of my FAVORITE---maybe favorite engine--of all time!!

Anonymous said...

I'm looking at a low milage 3.8 equipped car to purchase. This blog has been very informative. if I purchase this car, it definitely looks like my first task would be to replace the intake manifold BEFORE it becomes a problem. Maybe I missed your answer but what is the best option for replacing the orginal PLASTIC Composite Intake Manifold. Should I go with a factory part, look for an used one from another engine that is made differently (If so, what engine would work?)or go aftermarket(any recommendations)?

BernardL said...

Anon 1, GM did it because it was cheaper and lighter. Yes, the older 3.8 is a great engine.

Anon 2, yes, you missed multiple comments saying to use only the OEM redesigned new PIM. There are no short cuts. Fel Pro makes good gasket sets for them, but I only use the OEM plastic intake.

Glen said...

Bernard, Thanks a lot. I am trying to fix my sister's 95 Olds 88. Was our grandmother's car. Her mechanic said it was not worth fixing. I guess so, at the price he was charging. Not knocking you guys trying to make a living but $1500 seems high to me. Anyway, he didn't seem to understand the problem, thought head or intake was cracked. I pulled the plenum and found intake full of water.Also, starter nose cone broken. I assume he was trying to crank it with the cylinders full of water. Before I found your blog, I replace the plenum gasket, new plugs and started up OK. Drained oil, replaced with used oil to get the rest of the water contaminated out, filled with water and within minutes it was blowing white smoke. I pulled the plenum again and found the intake full again. I could not figure how so much water entered so quickly. Pulled the intake to check the lower gasket. Didn't look great but couldn't see where that much water could enter. Then I found your blog and had to read it twice, carefully. I checked the PIM to see if could be leaking. The hole was not apparent. After some scraping and probing with a pick I found it. I was about to put it all back together and check again. And it would have failed again. It's a relief when you can say for sure, here is the problem. Thanks, I will get the new plenum. BTW, the local part store carry a Dorman brand PN 615-180. I will check to see if it has a metal sleeve in the EKG hose opening before I purchase. Again, thanks for all your comments.

BernardL said...

Thanks for adding your experience, Glen. I hope there's no other damage due to the coolant circulating in the engine.

Eric said...

I have a 98 buick regal K engine. I am in the process of replacing my upper intake manifold with new gaskets and my lower gaskets. I am having a very hard time getting my lower intake manifold off. I am sure I have removed all the bolts but the thing feels like it is cemented in. Have you ever dealt with this when removing a lower and if so what was your solution? I counted 12 bolts that came out, which seems to match everything I have read about this procedure, and have spent a long time looking for hidden bolts. I have used a pry bar against a cast surface so as not to damage the aluminum but this thing will not even budge! Anything I might be missing here?

Eric said...

Ok, I got it off. My question now is what is the best way to get all the coolant out of the cylinders. My car experienced hydro lock which has led me to this repair. I have already removed the plugs and cranked the engine by hand with a breaker bar and cranked it with the key. I definitely got a lot out but would like to get it as clean as possible. I was thinking some of those long Q tips down the spark plug holes but would like to know what you do in these situations? Will the leftover coolant just burn out once the car is started?

BernardL said...

I have a thin walled flexible tube I made an attachment for to connect to my very powerful shop vacuum. It fits down the spark plug holes. I put whatever piston I'm cleaning all the way up and vacuum with my tube.

If everything is assembled properly on yours and you have clean oil and filter, all you can do is start it and hope for the best. When they hydro-lock, that's bad. Since you've been cranking it to get rid of as much coolant through the holes as you could, it should have started circulating clean oil everywhere. Bent rods, noisy lifters, and a lot of unknowns might be ahead of you upon start up. I hope it turns out well for you, Eric.

Eric said...

Thanks for such a quick response Bernard. Putting it back together today... (crossing fingers).

Anonymous said...

does gm use the metal gaskets on the lower intake manifold now?not the plastic

BernardL said...

I use Fel Pro when I do upper and lower intake manifold work on those, Anon.

Anonymous said...

Hi Bernard,

I have a 97 olds regency,exhibting all the traits you listed before.this vehicle was towed in a no start.I pulled the heads,upon removing the upper plenum the metal insert fell out.so I sent the heads out for a valve job/and to check the heads out,gasket set,new head bolts,upon starting engine just spins with slight popping,first I remove front vlv. cover,all rocker arms dry no oil reaching the top,mind you we have spark,fuel under pressure at the rail.so I remove the sending unit and crank engine and note oil only trickles out upon cranking.I drop the oil pan and find extreme sludge build up.clean congested pic up screen and blew filter inlet journal with compressed air.upon cranking now notably more volume.but oil wont reach push rods,and excessive valve clearance shouldn cause the engine not to start right? my question is low oil pressure do 3.8l have problems with the pump and engine dosent start any suggestions. appreciated :))
Karmie

BernardL said...

Karmie, yes, no oil pressure, no valve action, no start. The lower end will have to be rebuilt or replaced by the description you've given. It was probably run with coolant circulating in the oil for too long.

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BernardL said...

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BernardL said...

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Anonymous said...

BernardL.. THANKS for this Blog it is great, and I think you helped me solve a problem that has been baffling me for over a week. I have a 98 Buick with 120,000 miles. It has been running and driving great, but I actually open my hood every now and again to check my fluids. Well I have been noticing that I am loosing coolant. I COULD NOT FOR THE LIFE OF ME FIND WHERE !! I even went as far as to dye the coolant, and I could not find an external leak. I also showed no signs of a bad head gasket, my oil looks fine, no huge pressure increases in the cooling system when running, no smoke, etc.. However three times within the last 2 weeks I had a misfire on number 6 when I started the car. I thought it was a bad plug wire and did a full tune up over the weekend. Since I am still loosing coolant I now suspect I have a crack in my Upper intake as you described. My question is this baring removing the throttle body, is there any way for me to get the UV light in there and check for dye. If the throttle body must be removed do you think the gasket will be able to be re-used or should I have a spare standing by?? Thanks JOSH

BernardL said...

Josh, look at the underside of your oil cap. If you have any creamy residue or dots of moisture, the coolant is already getting into the combustion chamber because of the manifold. With that many miles, forget the UV light and change that manifold if it's never been replaced, using the updated OEM manifold and Fel Pro gasket set. Once the throttle is removed you will be able to see the coolant inside and the burned EGR passage, and probably it will shine under UV light inside.

Anonymous said...

First I would like to thank you for your help with mu last post about loosing coolant but not leaking. The car did indeed have a bad intake manifold and was dumping coolant into the intake. I have no idea why it was not blowing white smoke, but it was full o dyed coolant. I did not even an ultra violet light to see it it was just green all over !! All and all it was about a 4hr job, including 30 min of trying to get the PVC valve back in.

Now for the next issue, the car is running very cool. I replaced the thermostat today thinking that may be the issue, but it is actually running even cooler now. I believe the issue is that my fans are running all of the time (well whenever the HVAC is on even its on heat). Where is the temp sensor for the fans?? What else can the issue be?? THANK you once again in advance !!

BernardL said...

Anon, the thermostat should be a 195 degree thermo. The fans are supposed to come on if defrost or AC is selected. An AC pressure sensor acting up may be causing them to come on, or a stuck relay, or a malfunctioning body control computer. I'm sorry, but you may have to take it in to be diagnosed.

J. said...

Hi Bernard,

Thanks for such an interesting blog. I too have had experience with the UIM/Dex-Cool issue. I had it replaced or so the repair shop stated. They said that they tossed out the parts because I did not ask them to hold unto them for my inspection.

Two years later my car started to overheat I pegged the temp. gauge. I pulled into a parking lot and the red temp trouble light was showing and just as I pulled into a parking spot the engine died. It turns out that I'd blown the "lower radiator hose" off The smell of burned oil rose as I lifted the hood. To make a longer story short. I was around the corner from the same shop that had "done" the Dex-Cool work. Now under new management, I explained everything that had transpired.
After examining the engine, the manager indicated that I had either a blown head gasket or one/or more cylinder heads were cracked. To find out what the problem was That it would cost about $700 to take the engine apart to determine if I had another Dex-Cool issue. Additionally, to check the cylinder heads would cost about another $300 or more. The car isn't worth that - rusting undercarriage and too many dings and dents.

I asked how safe it would be to drive the car home (about two miles). He stated that if I tried driving home to get it off of his lot, that I would probably blow the engine up. Well. I did drive home and no it did not blow up. I needed transportation. I topped off the radiator with water - that is what he had used to partly fill the cooling system so as to pressure test the system. I drove around the neighborhood with no issues. Feeling more confident that it was safe to take it on the road. Still no problems. Then I took it out on the freeway. Punched it to the floor and held it there until the governor kicked in. Well, I've now driven it for the past 5 months..

I have a 1997 Grand Prix GT, 3.8 L 3800 Series 2 engine.

However, I now have a different question/issue for you.

I have had the oil pressure light come on 3 times in the last two days and the engine quit the last two times. I tried to restart the engine a couple of times before it started (the last time I tried, I held down the gas as I cranked the engine, it finally caught and stayed running) and it ran w/o any problems. Did my shopping started the engine and drove w/o and problems of any kind (about 3 miles). Just as I pull up to my front door. It died again. I unpacked my car. I started it so as to park it. It did so up with no problems, and I parked it w/o any more issues. The engine seems stall out when I've taken my foot off the gas either to coast or to apply the brake.

The first time I pulled to the side of the road. Pulled the dip stick - the level looked low(even though when I pulled the dip stick it seemed to be registering at the bottom of the stick) I tried it several times. I added about 4 oz! That seemed to bring the level back to the upper level of the crossed hatched area of the dip stick - Yeah, I know that that doesn't make much sense. Started the car back up and continued on to my destination (about 1 mile) w/o any more problems. After about 4 hours went back to the car, started it up and travelled about 9-10 miles (45 MPH) until I was home - again w/o any more problems.

Any ideas and probable costs involved?

BernardL said...

J, first off, you went two years after their service with no problems. That is a long time. Nowhere in your comment do you say whether they replaced the upper plastic intake, nor any diagnostic information for me to give you any advice on why it’s stalling so here’s my best guess. The overheating episode may have been because of gradual loss of coolant or a sticking thermostat or the intake leaking. Filling it may have gotten you back on the road, and at that time you may have only had the intake leak described in my post. Since driving it without a diagnostic check or any repair for five months, you’re now experiencing the later symptoms of coolant mixed with oil: oil pressure problems and lower end damage. If you’re hearing clacking noise when you first start it up going on longer than ten seconds, and the underside of your oil filler cap has a milky substance on it, and it’s the rusted hulk you stated, my advice is to get rid of it. You might as well put any money now into an upgrade.

J. said...

Supposedly, the UIM gasket was replacesd as well as the upper manifold itself. I did have the the oil tested for hydrocarbons in the last month-and-a-half(@ local auto tech school.) They did the hydrocarbon test (chemical did not change color indicatiing such and said no hydrocarbons.) They also flushed the radiator(water-only no high-pressure or flush agents used, again I had only had water in the cooling system from the beginning of July through mid-October. I probably put 900 or so miles on it, after I got it from the repair shop. I’ve probably put another 650 since the auto school did the above-listed work. They used a 50/50 mix of a nonDex-Cool coolant and replaced the thermostat, they did not indicate that was anything "odd-looking' in the fluids or on the parts that they replaced. I have been getting normal temperature gauge levels and getting heat in-cabin now that its gotten cold. When you say, "Since driving it without a diagnostic check", like what are you talking about? Examples, please other than the items that I mentioned above. Oh, I did have an acquaintance pull sparks plugs, who indicated no kind of fouling or I think it was called "thermal-burn marks on the plugs, no white smoke coming from the tailpipes, no sweet-smell of coolant in the oil.

Today, I looked under the oil cap - no white/gray nor any kind of buildup and the coolant overflow bottle is still about midpoint in the bottle after a bit of driving and having reached operating temperature (about the 1/4 mark on the temp. gauge). The color is greensish.
Is it likely that it simply is an oil pump that is reaching its end-of-life, or any kind of sediment build-up? What would I look for? Oh!, the car sat on the repair shop lot for about 2 1/2 months during a pretty hot summer (my health-issues and no one to follow me home in case the engine did blow up). It was so hot that the heat buildup in the car got pretty intense and cooked the day/night mirror (it doesn’t work as it used to work).

BernardL said...

J, if you have no coolant leaks, no engine noise, and no milky substance, then take it into a good shop and have them do a diagnostic check on it for the problem you're having. They should do an in depth computer scan for the stalling, and oil pressure test to isolate whether it's the pressure or the pressure sensor.

J. said...

Hi Bernard,

sorry for taking so long to get back to you to say thanks for your help. It turns that when I took it in for the oil pressure light that, they found that I now have a coolant in the oil issue. I had checked the oil filler cap and there wasn't any white discoloration under the cap before I took in for them to look at. It turns out that the engine service light that I did not tell you about was a code for the mass air flow sensor being triggered . So, it turns out that I have multiple expensive repairs. They indicated that sometimes coolant in the oil AND/OR the MAF can trigger the oil pressure light. Again, thanks for the time and energy that you used to assist me on your blog! It is very much appreciated.

Anonymous said...

Hi,2001 Impala with a 3800 non-supercharged, I was trying to start after the owner pulled the radio out and was going to install a different one,he set the security system off and was unable to start the car.I replaced the radio and I reset the security system and attempted to start the car, it turned over a couple of times and then the upper plenum exploded and it caught fire. My questions are, what should I be looking for in attempting to repair this? Do you have any idea why this happened or what caused this, your help and suggestions would be greatly appreciated. The car ran fine before he tampered with the radio. Thanks Mike

Anonymous said...

Hey i have a 1997 buick park avenue, i know this is a common problem but coolant is getting into my engine and burning lots of white smoke but do you think its the upper or lower intake manifold?

BernardL said...

Thanks for the update, J.

Fuel pooling in the manifold due to leaking injectors or faulty fuel regulator coupled with a backfire from the vehicle not being started for a few days is about the only guess I have, Mike. Unfortunately, I can't tell you how many things you'll have to replace to get it running from on the Internet. You'll have to take it in for an estimate at a reputable shop.

Anon, you'll have to have the upper intake replaced if the coolant is pooling inside the plenum chamber. Read the blog post you're commenting on. Whether you have other problems with bad head gaskets or cracked heads or lower engine damage will have to be examined at a shop.

beatnick60 said...

Enjoyed your blog- it helped with my son's Park Avenue. To thank you I bought Cold Blooded and read it on my Kindle. It was great!- You're a very good writer! (And under cover of being a mechanic, probably a very good assassin as well!)

BernardL said...

Thank you, beatnick60. I'm glad you enjoyed the novel. It would help if you could paste the same review at Amazon. No matter though, I really appreciate the feedback.

neenee said...

Hi I am having so many problems with my 2000 impala. New Years Day the car just shut down I got a boost off and it started back running but after about two minutes it started smoking I replaced the battery and started the car. At that point I had a small explosion which sound like a gun. The explosion blowed the oil cap off and cracked the engine cover. Also it blew some plastic piece off that smelled like oil. The heat does not work anymore neither does the air. My interior lights stopped coming on and the oil light is always on someone please help me what is wrong with my car

neenee said...

I also have 3.8L motor

BernardL said...

Think about it neenee, how can anyone tell you what's wrong from the Internet? You need to have your vehicle taken to a shop for professional diagnosis. It seems from what you've written that you may have put the decision off far too long already. The time to have it checked was when you first had trouble starting it.

neenee said...

All of this just happened on new years and i haven't driven it since then.I had some of the same problems that other people on here had and thought I could get some type advice. This a very small town and getting a professional to come here seems to be impossible. However, thank you for your time

BernardL said...

Try this site to find a professional shop near you, neenee. A hands on inspection is the only course of action for finding out what's wrong.

http://autorepair.iatn.net/

JasonM said...

Thank you so much for the info on this post! I notice this was a very old post, so I hope you are still paying attention to it. I am already thoroughly aware of the problem, as I currently have two W's with this problem. (I think) 00 Grand Prix GT, and 96 Regal Custom. The Buick is taking the worst of it, as it is higher in milage and also had a minor leak in the radiator. They both exhibit the symptoms for this problem. (Milkshake inside oil cap, losing coolant, also I noticed what appears to be ehaust gases coming through to the coolant resevoir) Is that last one weird for this problem? Was thinking maybe head gasket problems also due to the dexcool garbage that's in it combined with the leak and EGR stovepipe/UIM problem allowing air to stay in my cooling system? Unsure about that one myself as I have as of yet not found any "milkyness" on the dipstick of either car.

So, here's my questions; 1 how do I tell the difference between the dorman UIM and OEM one? I am very low on funds at the moment and am hoping to maybe salvage a dorman intake from the junkyard. I'm trying to save money any way I can as I can barely afford the gasket sets alone for both upper and lower manifolds right now. 2 I read about people who replace the EGR stovepipe with a reduced diameter one which is then sleeved with stainless steel and cemented with jb weld and used in conjunction with the OEM manifold. Have you heard of this? If so, does it really work? And I'm not sure how I feel about trusting the inside of my motor with self applyed epoxy, what if some of this somehow made it into a cylinder or something? Anyway that would be if I was lucky enough to find an UIM in the yard that is not already ruined. Not probable I'm thinking. 3 both cars are workhorses and me and my family depend on them for income, so I need to have them both running at least for another 20-30 thousand miles. By then I will be able to get another motor for at least one of them. So, do you think there is any way at all I could skip LIM gasket, get a used OEM UIM (or maybe jb weld around the stovepipe of my bad one?) to save money to go towards a used motor? That would leave me to only buy the upper gasket kit, right? Probably dreaming, but I'm looking for the cheapest dirtiest way to stop the coolant from burning/ruining my oil to just get another 20,000.
Anyway, I've probably got a million other questions about this as I am just a backyard guy with the tools and the drive to learn as I go. But honestly, any help/advice you can give me would be greatly appreciated. And might even help me save my job. So, thanks in advance.

BernardL said...

My advice is to park them all until you can get new OEM only parts and OEM or Fel Pro gaskets, Jason. I'm sorry but there's no other way on this particular job but the right way.

Anonymous said...

I attempted to perform what I thought was going to be some simple maint work.... replace the lower intake manifold gaskets...and then install new aftermarket Dorman upper intake manifold. We very careful with the tear down and install...and followed all torque specs.

What I have is a P0507 (RPM too high...intake leak) and have ton of oil in the upper intake manifold. So much oil that it's causes car to blow blue smoke for a minute or two when first start it up. That means when the car is parked....residual oil is leaking down from the intake into the cylinders.

Why is there so much oil in the upper manifold? Where could the P0507 be coming from. I had sprayed starting fluid around the upper intake when the car was running to see if I could find an intake leak but all was dry and tight from the outside of the UIM. I've got the upper intake manifold removed again and it's such an oily mess inside.

Any ideas? Thanks!

BernardL said...

Anon, I can't help much with your problem from the Internet. If you didn't have a problem before you did the job, then it is reasonable to assume you've done something wrong during install. If you're going to do the job again yourself, I would recommend finding a factory shop manual. The second thing is I don't install aftermarket upper intakes so I don't have any idea if you've missed something by installing the Dorman. Third thing, NEVER use starting fluid to look for vacuum leaks, unless of course you want to end up on someone's 'Darwin Awards' joke list posthumously. I'm afraid tearing the whole job down again and reassembling with factory manual, OEM parts and Fel Pro gaskets may be your only option. You've done something wrong during assembly.

Anonymous said...

I have a 1998 Pontiac Bonneville SE, with a 3800cc Series II, not supercharged, which I purchased new in 1998. In Jan 2004, at 121K miles, it blew out the intake manifold. My wife was driving the car. She described copious white smoke and liquid coming out of the exhaust until she turned the engine off. It did not ever stop running. The upper intake manifold and gaskets were replaced by a Buick dealer. The lower gaskets were not replaced. I have the receipt. The car has run well since.
Over recent weeks, now 195K miles, I'm getting two EGR codes (P1404 and P0404) and a cylinder 6 misfire code (P0306), repeatedly. The engine is consuming coolant at about a pint of coolant per tank of fuel. I can find no sign of external coolant loss. No white smoke. No milky oil on the dipstick or under the oil filler cap. Oil consumption is about a quart per 3000 miles.
I have seen elsewhere that in July 2004 GM issued a service bulletin instructing use of a redesigned upper intake manifold for this repair. I suspect that was too late for my Bonneville, and I got a second defective plastic upper manifold.
I have studied your blog and thank you for it. My 17 year old son now drives this car and he loves it. I loved to drive it from 11/2004 until 10/2010 when I passed it to him.
My plan at this time is to 1) replace the upper manifold with a new genuine GM OEM upper manifold and 2) remove the lower manifold and replace it using the Fel-Pro Gaskets. The factory shop manual is on the way to me. I expect to also replace AC/Delco spark plugs, injector o-rings, thermostat, PCV, coolant elbows, all coolant hoses, oil, and oil again every 500 miles for 2 changes.
My questions are: 1) Do you agree with my plan? 2) Does the GM manifold come with its own gaskets or should I try to get a Fel-Pro upper manifold gasket (I can’t find one.)? 3) Is replacement of the lower manifold gaskets necessary, or is this more of a preventive maintenance item to upgrade to the improved Fel-Pro gaskets while it is easiest to do so? 4) Can I clean up the EGR valve and try to continue using it ($150! and accessible without the tear down, I could replace it if the EGR codes persist) or should I replace it, too? 5) What is the difference between the original and the 'Second Edition' factory shop manuals?
Thank you again for this blog, and in advance for your reply.
Greg

BernardL said...

If you’ve read my other comments you know that if coolant has been circulating in the oil for some time, it will be a gamble no matter what you do at that mileage. After you finish the job, you may still have lower block failure. Is there a thick creamy substance on the underside of the oil cap? If there is, then you’ve been running coolant mixed oil and no matter what you do, it will be a gamble.

As to your question, yes you need to change the lower intake manifold gaskets too with a complete Fel Pro set. You can hold off on the EGR valve until you see how the intake job goes. As the pictures on my blog show, it’s the EGR passage that causes the problem with the upper intake. The first thing to do on your vehicle is a compression check. If any of the cylinders are low, it would be senseless to do the intakes.

If you don’t think the lower block is in danger of failure, and the compression test is normal, I would only add two items to your list – one would be a set of fuel injectors. You can purchase a complete set on-line here: http://www.lindertech.com/reconinj.htm - get the lifetime guaranteed Bosch replacement set. You don’t have the ignition wires listed either. That’s a must.

Anonymous said...

hi-99 buick lasbre 3.8 eng.calls for a 195 thermost--what if you un a 180 ther. what it will it do

BernardL said...

Anon, running a cooler thermostat will cause the engine in many cases to stay in open loop too long and it will flunk smog tests, and cause reduced gas mileage. You want the coolant temperature sensor to trigger computer controlled fuel use as fast as possible. A cooler thermostat defeats that objective.

Roy said...

My son has a 99 Bonneville 3.8, recently started having an intermittent problem where car's temp. will go up but not quite all the way to overheating. When this occurs the heater quits blowing warm air, only blows cool. Other times heater works normally and engine temp normal. Replaced thermostat, no change. Wondering about the plastic manifold, 140K miles, never changed.

BernardL said...

Roy, you may very well have problems with the intake, but what causes the heater to quit along with creeping temperature is a head gasket or head problem. As in many of the other comments here, you can take the oil cap off and turn it over. If it has creamy colored residue on the underside you're getting coolant into the oil. As I mentioned at first though I believe you have a more serious problem.

Anonymous said...

Alright Bernard, I have to say I'm pretty impressed with your knowledge of the 3.8L. I have a 1998 chevy camaro with the 3.8 v6, vin [k] with an intermittent problem. Normally I value myself as somewhat of a decent mechanic, and have babied my car since I purchased it. As you have said, these engines are notorious for their intake gasket failures, as well as their leaking heater hose fittings; as well as some other minor issues. The car has roughly 122,000 on it, and intermittently surges at startup in park. Battery voltage and RPMs synchronously change together, surging from initial idle of 950 rpm, down to 400/500 to 1200/1500. I have been plagued by this for nearly a year, and have ran extensive tests with no avail. I have replaced the MAF, TPS, IAC, spark plugs, wires, battery and alternator. I also have an intermittent bank 1 sensor 3 O2 sensor code, but have disregarded this as it shouldn't have an effect on the initial startup or overall wellbeing of the engine in park. The issue only persists in park, and lately I have been smelling the catalytic converter beginning to go out. As I said, I'm stumped and any help would be very much appreciated.
Thanks, Chris

Bernard Lee DeLeo said...

Chris, my guess would be plugged cat. I would do an exhaust back-pressure check in front of the converter. A plugged cat may set a B1 S3 code. Since there are four B1 S3 codes, which one did yours set?

Anonymous said...

I had a 1998 Buick with a 3.8. bought one week. drove 1300 miles and engine was done and seized. Coolant was dissapearing and did not know why. Until it was too late 150 miles from home. dealer blamed everything on me. going to court now. lol thanks

Bernard Lee DeLeo said...

That's awful, Anon. I hope you're able to get something back. Once that coolant starts leaking internally it can happen very fast.

Anonymous said...

HI--I HAVE A 2007 HHR-CHEV.
THE AIR CONDTION STOPPED WORKING-THE CLUCTH ON THE COMPRESSOR DOESNT KICK IN--ON THE FUSE BLOCK IT SHOWS NO.15 A/C COMPRESSOR--IT IS A BLOCK LIKE A RELAY OR A BREACKER--WHAT TO YOU THINK IT COULD BE?
THANKS--DALE

Bernard Lee DeLeo said...

Dale, that's impossible for me to guess at from here. The PCM controls the ground which energizes the AC Clutch. The low pressure sensor also affects whether it engages, as does the control head itself.

Anonymous said...

i have a 1998 buick century is there a way to get the hole on the return also with the different engine?

Bernard Lee DeLeo said...

Anon, if you buy a used engine, yes, you may get the older type intake. If a rebuilder is supplying the complete engine, they would be insane not to change manifolds to the updated one. Unfortunately, I have no way to know that. You need to ask specific questions of the rebuilder.

Anonymous said...

mr.bernard--hello-i have a 07 hhr chev.--the a/c--had it chared with freon--found a leak in the cond.- the freon all leaked out in 24 hrs.-put in a new cond.the man tryed to charge it with those small cans of freon-but i would not take it--he said the comperssor
was bad---the first guy that chagerd it--it worked--so why wont
it take thoses small can?what do you think?
dale

Bernard Lee DeLeo said...

Anon, you need to take your vehicle into a professional. Those systems have to evacuated and recharged properly, not in someone's backyard. Please get a professional to fix your AC before you damage it to the point where your bill will truly be astronomical.

Anonymous said...

Hi. I have a 2003 park avenue with the 3.8. It does not have any of the other issues you have stated about oil and coolant but it does idle and drive rpms extremely high . Have been told possibly bad intake. Can intake cause that issue without having oil and coolant mix?
Thank You Charlie

Bernard Lee DeLeo said...

Charlie, any vacuum leak around the intake manifold or throttle body can make the engine surge, or have high RPM's. Most vacuum leaks can be found quickly by spraying around suspected areas with a fast drying Brake-Clean type spray (never use anything volatile). However, some vacuum leaks require the use of a Smoke Machine, that introduces a vapor into the intake which will come out through any opening.

With vacuum leaks, the car should be setting Oxygen Sensor codes for a lean mixture. If there are no codes, there may be a problem with the ECM (on-board computer). I really don't see any alternative for you other than taking it into a professional shop for diagnosis if a vacuum leak can't be found easily that is causing your problem.

Anonymous said...

Thank you
Charlie

Anonymous said...

I have a 98 Monte Carlo With 260000 on it I Replaced The Plenum And gasket runs great. after a couple days it started to lifter tick at cold start for a few minutes then stops. the gasket blew going down the road but i stoped as soon as i noticed missing and trailered it home. ive been a mechanic for years just woundered if you have a clue what it could be. I change tne oil every 3000 miles and its do again. im going to change it before i do anything major. i always vse valvoline convetional but last time i ued the valvoline max life you think i should go back to the coventional? thanks Sam

Bernard Lee DeLeo said...

I didn't quite understand whether you found that coolant was contaminating the oil from a bad upper composite intake that you replaced and fixed, or you did the work and you still have the lifter noise, Sam. If you did the work and you still have the noise you may have damaged something in the lower end with coolant contamination, especially with that many miles. If you're going to keep running it until it gives up the ghost, then put in full synthetic Mobile 1 or Motorcraft 5w-30 oil. Keep changing it at 4 months or 3,000 miles. If the lifter noise keeps up, it means you have low oil pressure caused by the coolant contamination. It's new engine time then.

Anonymous said...

thamks. i changed the oil and everything seems to be fine. talk to you again

sam

Bernard Lee DeLeo said...

That's great news, Sam. I hope there's no more complications. Thanks for the update.

Anonymous said...

Hi-Bernard--
on a 99 buick lasbre-when you install a oil pan gasket do you use a sealent on both sides of the gascket? if so what kind do you use?
thanks-dale

Bernard Lee DeLeo said...

Yeah, Anon, I do on that one. The other big problem is the rear main seal plate and rear main seal leaking. I'm not sure from your comment if you're experienced, but that oil pan job is not an easy job. Add in the rear main seal and plate gasket and it is a rough job. The engine has to be supported with a special support bracket tool on top, and the sub frame has to be lowered to provide clearance. The directions in a very good shop manual have to be followed step by step.

Anonymous said...

2001 Le Sabre with 3.8L engine. Car wont run because the timing chain failed and engine is out of whack. Wife tried starting it for what ever reason and blew the top off the cold air intake manifold. Could this be from a clogged Cat Converter when the timing went casued by back pressure. (Wife drove 300 miles when engine was running rough)or because the timing is off on the cylinders causing excess fuel to reach manifold from a cylinder and incomplete combustion. Car turned over but would not start prior to this incident. Replaced crank shaft sensor and checked for spark and fuel which all seem to work fine. What is my next step that I can do to save a little cash prior to sending to the shop for repair work on the timing belt. Car has 130 miles and up to date on oil changes and maintenance. Thanks

Tyler

Bernard Lee DeLeo said...

Impossible to say, Tyler. I'm sorry, but you need to take your vehicle into a professional. You may have problems that are in excess of expense feasible to fix the car.

Gregg said...

OK SECOND TIME TO TRY THIS. I GUESS I'M OFFICIAL NOW. Mine is a 2002 Lesabre all original, well maintained, 132,000 miles. I have the plenum-upper intake off and it looks superb! Can it be? I expected to see some melting. Car had a tiny coolant leak on lower manifold to outside. Is it only fooling me? Is it gonna melt down after i put it back together? Thanks, Gregg

Bernard Lee DeLeo said...

Gregg, according to GM, they fixed all the problems with the composite manifolds by 2000. Most of the ones I've done in the years after 2000 all had to do with lower manifold leakage problems.

Gregg said...

Why thank you for that reassurance. Like you I have my own shop (pay taxes and all) out of my home. I could not however find any where stating GM had fixed the prob. God bless, Gregg

Gregg said...

Bernard, another question. FelPro makes a cheaper and costlyer (?) lower gasket set for this motor. except for the injector o-rings no difference really in content. is the expensive one THAT MUCH BETTER or is it only for if you have warpage (heat) problems? Any clue? Thanks again, Gregg

Bernard Lee DeLeo said...

I always get the more expensive set, so I'm not sure, Gregg. It may be the only difference is the injector o-rings, which although I probably don't need to, I do use.

Gregg said...

There has to be a quality diff. cause o-rings are only $10.00. The diff. in cost is either $40.00 or $75.00 at least down here in southern New Mexico anyway.

Bernard Lee DeLeo said...

I can't answer that, Gregg, because as I explained, I only use the upper end one.

darren perkins said...

Bernard I just tried to start my 2001 Buick Lesabre this morning and when I turned the key I heard a loud bang and smoke came rolling out from under the hood. The intake manifold was blown to pieces. Oddly enough the car still starts but surges crazily. Is this car now junk or can it be fixed do you think??

Bernard Lee DeLeo said...

Darren, I'm sorry, but until you determine what caused the backfire, anything you do will be a gamble. Many things can cause a backfire: Ignition miss, blown timing chain, fuel injectors leaking into the cylinders overnight, plugged catalytic converters. It's impossible for me to tell you anything over the Internet about something like that. My advice is have it checked out professionally.

Mike said...

Hello Bernard,

I've read thru all the comments in this Blog and I must say that you seem very knowledgeable regarding the 3.8L I am going to go look at a 2003 LeSabre with 54K on the clock. It has the 3800 Series II. Besides the obvious (condensation in the oil cap, low coolant in the resevoir, coolant on the LIM) is there anything else you suggest I look for as it relates to the coolant leak issue? Also, do you know if this is an issue that appears with age or mileage (thermal cycle)?

Regards
Mike

Bernard Lee DeLeo said...

Mike, according to GM, they are not having any problems with the composite manifolds now, unless there is exhaust backpressure as in plugged up catalytic converters. They also still have problems with the lower manifold leaking coolant and oil.

Rodney Queen said...

I am thinking about buying a 2002 Pontiac Grand AM GT with 116000 miles on it. anything I should be on the lookout for. Cant perform compression test on it where it is at, and know of no mechanics near the sellers area. Thoughts?

Bernard Lee DeLeo said...

The best thing you can do before buying a used car without having it checked at a professional shop is to make sure everything works on it: lights, heater, defroster, vents, transmission shifts, air conditioning, the way it runs, condition of tires, belts, hoses, wet oil on engine bottom, coolant condition, etc.

Then ask about maintenance records. The owners that do them religiously, keep track of them. My advice has always been if there are no maintenance records - walk away.

It's a gamble even when you have a pro check it Rodney, which is why maintenance records on oil changes, coolant flushes, and trans servicing are important.

Rodney Queen said...

All of the previous conversations on the 3.8 re. leaking coolant have me worried. what else, besides looking for creamy oil and discolored radiator cap should I look for, or am I being picky? 170000 miles for a beautiful car @ $2500?

Bernard Lee DeLeo said...

Rodney. That's about all you can do. Remember, most of GM's problems came in the 90's with the composite manifold. They corrected the flaw by the 2000's. Mostly, the later models have some problems with lower manifold oil leaks.

Don Duke said...

Finally someone with good experience and knowledge offered at no cost who seems very genuine with results dating back nearly 5 years and still to date offering a helping hand! AWESOME.. I recently replaced the UIM on a '97 Park Avenue. Went through all the proper notions with care and precision as I always do.. Upon completion it ran like a champ and still does! Vehicle ran and was driven for upwards of two hours without an issue!!! Five hours later I moved the car from the street to the driveway and upon shutting down I smelled a strong fuel oder. Up inspection fuel was everywhere around the injectors! My number 1 question is with the injector o-rings included with the Dorman Kit. It had 6 Black and 6 Yellow o-rings for the injectors. Are they specific to top one color and bottom the other color and does it make a difference??? Black on top with Yellow on bottom or vice-verse!?? Im done for the night and will get back to it in the a.m. but as for now I have been stumped and searching the net like a damn fool! Any insight would be greatly appreciated. Thanks Again....DON

Bernard Lee DeLeo said...

Don, here's a link to different injectors showing some color difference.

http://www.robietherobot.com/storm/fuelinjectorguide.htm

It shows the yellow ones where illustrated, going on the bottom. I always use a Fel Pro gasket set. They're all black, but the size is slightly different. Check out the pictures carefully after you get the injectors out again. It's possible one of them is cracked too, or cocked slightly.

Bernard

Wayne Robb said...

Good day Bernard,
Thank you for all your comments on this subject.
I own a 04 Buick Regal with the 3.8 none supercharged engine. When I accelerate going uphill to maintain my speed I notice the ac/heater fan getting quite as if I was turning down the speed of the fan. It could also be changing the airflow from defrost to floor, I'm not sure. Is the airflow controlled by vacuum pods? And if so, does this indicate a vacuum leak? Your help would be appreciated.
Also, the common problem of LIM gasket leak you mentioned in this blog, is this a internal or external leak? What would be the consequences of this problem? Thanks again, Wayne

Bernard Lee DeLeo said...

Wayne, those have a couple problems that can cause blower erratic speeds. The vent switching adds a different problem that may have to do with the HVAC Control Module. Those modules cost over a thousand dollars from the dealer if that is the problem. There is an outfit that rebuilds them - Boulder Brothers Module Repair in Medford, Oregon - http://www.boulderbros.net/

The Blower speed has a Blower Motor Control Module which acts up.

The 2004 model doesn't have the intake problem like the mid nineties 3.8L. You can wait for the blower problem to be more pronounced to have it checked, but I don't see anything you can do other than take it in for diagnosis.

Wayne Robb said...

Thanks for your quick response. I'm glad that the 04 does not have the same problem of LIM going.

The problem with the heating/ac is only when I use more throttle so this is why I thought of the vacuum pods controlling the heat/ac to change from vent to floor and back to vent when throttle is released. The speed of the fan was the first thing I thought was slowing down but I think the speed of the fan is remaining the same and its the changing of vent to floor which I think makes it seem that it is the fan speed. What controls the mode? I thought it was vacuum pods.

Bernard Lee DeLeo said...

Like I stated, Wayne, my guess would be the main HVAC Module. My suggestion would be to let it get a lot worse so there will be no question. Also, if you want to investigate further, check and clean all grounds.

Wayne Robb said...

Thanks Bernard,
I'll give Boulder Brothers Module Repair a call. Thanks for everything! It's nice to know there are people out there trying to help others without any compensation. Your doing a great job.

RankAmateur said...

First, thank you for this awesome blog.
I have a 2003 LeSabre with the 3.8 V6. It had 30,000 miles when I got it a year ago, now 39,000.
It had sat unused for two years, but once it got a new battery, it started, and it has run well since then. No "codes".
Recently, at the start of heater season, I smelled coolant. A good, honest local mechanic says the PIM has warped and coolant is leaking. (I am not even a good STM.)
There is no residue on the oil filler cap. The oil on the dipstick looks normal. It burns a quart of oil in about 6,000 miles and the exhaust seems normal.
I am happy to spend on preventive work. I very much want to avoid breakdowns.
Thanks to you, I see that that the shop should only use the redesigned OEM part and the Fel-Pro or GM gasket kit.
My questions are:
Is there other work that I should get done while the shop replaces the PIM?
How likely is it that other parts of this engine have been damaged already?
Should I have tests done, or extra teardown and checking-out?

Bernard Lee DeLeo said...

The 2003 has the redesigned PIM, Rank. Other than doing the work and correcting the problem, I would switch to changing the oil and filter more frequently than at 6,000 miles.

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