# GM plastic intake gaskets



## Tommy2 (Nov 25, 2008)

I have a '98 Buick with the 3.1l engine (basically the same, I think)

The lower intake leaks too.. Like you said, it was a real big problem.

I think the pink radiator fluid they used was a problem too. (turns acidic, Ive heard..)

Ive had the car for around 50,000 miles and its never gotten worse. (now with 150k). I just add stop leak to it every once in a while. 
I know its just a band aid..but changing that intake would be a pain, and Im an automotive guy. Not something I want to tear into..
The stop leak has kept the leaking to a minimum for 50,000 miles..so no reason to fix it, really.


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## 4just1don (Jun 13, 2008)

so my question is,,,will it leak coolant INTO the oil which is a death call waiting to happen???


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## polarzak (Dec 1, 2008)

4just1don said:


> so my question is,,,will it leak coolant INTO the oil which is a death call waiting to happen???


If enough leaks in, you can severely damage your engine. This does not happen to ALL engines.

Have had a 3.1, 3.4, and 3.8 all with over 200k miles and no problems, although the 3.8 was losing a small amount of fluid before I turned it in. There was a class action suit launched in 2008 for the 3.8 problem, however you had to sign on by November.


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## MgMopar (Jul 31, 2004)

Yes, They do many times leak coolant into the oil (_bad_ can wear out of ruin a engine quickly). They are a problem. Not to many special tools but a rather large job for the average Do it yourselfer. I believe Fel Pro is making a new type of gasket for most of them now that has a metal area surrounding the O ring style seal that is more reliable the OEM plastic design.


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## frazierdavidson (Jan 31, 2009)

*gm plastic intake gaskets*

G.M. has a revised gasket for these applications. Unless your pretty good
at mechanical repairs, I wouldn't suggest starting with an intake gasket.
You could create more expensive repairs than you fix. Flat rate time to make reoairs is about 6 hours and parts should probably run two hundred
dollars or so. If coolant is leaking internally, it can do some major damage.
Check your oil, if it looks like a milk shake, I wouldn't drive it..


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## oregondiy (Oct 24, 2008)

I wouldn't advise it, but if you attempt this repair yourself make absolutely sure you put the pushrods back in the correct locations, they are 2 different lengths.


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## MT Stringer (Oct 19, 2008)

My 98 Chevy P/U is in the shop right now getting the intake gaskets replaced (189,000 mi). They also found a water leak at the heater hose connection. Quote is about $600 due to the labor intensive gasket change out. Hopefully, they caught the leak before it has caused damage to the engine.
Mike


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## grumpypapa (Feb 11, 2009)

*Look*

alot of people dont know that just because there isnt a recall there is such a thing as a service advisory in which dealers will make such repairs at little or no cost to you the consumer. I dont know if there is one on these troublsome motors but check your local reputibal gm dealer and ask about a service advisory. I had a 1999 f-550 roll back that had clutch problems and there wasnt a recall but after a big run around from a not so reputibal dealer another in the area found that there was a service advisory and the clutch system was repkaced from the pedal to the fly wheel. hope this helps good luck


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## frazierdavidson (Jan 31, 2009)

I would't bank on any factory assistance on the intake gaskets. Oldsmobile dosen't even exist anymore, and given the state of G.M. finances, I would doubt any special policy would be issued on a vehicle that old. I suppose a class action suite could come about, but given the age and high mileage on vehicles that old, it probably won't happen..


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## HawkZ28 (Feb 18, 2009)

It's a common problem on those engines. I just did our Grand Am over the summer, and it was only about a 6-7 hour job, including replacing the AC condesner/dryer, changing spark plugs, PCV, oil/filter, descreening the MAF, adding a CAI and cleaning the TB, MAF, and K&N . 

Just be sure to get the EXPENSIVE gasket set- I think it was about $75-85 at Advance.

Plan on that gasket set lasting about 75k or so.


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## GrandMasterTech (Dec 3, 2010)

4just1don said:


> so my question is,,,will it leak coolant INTO the oil which is a death call waiting to happen???


Hi there if the leak is external then you should be ok. But WHEN it leaks internally then ur screwed. I'm a general motors technician and I know this is common there is no recall but you must get it done. Some places charge less than the dealership but at least at the dealership you know it's getting done right. I suggest you buy aftermarket gaskets that are metal instead of plastic and install those. Also make sure while you are there you charge the thermostat and the oil pump drive shaft seal. Messageme back if you need more detailed instructions. I can do an intake job win my eyes closed. Lol! I've done hundreds. Usually oy takes me 2-3 hours


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## GrandMasterTech (Dec 3, 2010)

oregondiy said:


> I wouldn't advise it, but if you attempt this repair yourself make absolutely sure you put the pushrods back in the correct locations, they are 2 different lengths.


Yes that is a key point the long push rods go under the gasket that is what I always keep in mind. Also make sure that you torque the rocker arm bolts to the correct spec for that engine. Alot of times people torque the 8pm bolts to the same torque As the 10pm bolts and after driving it for a while it will stripp and pop out other head. Then you will have to change the head gasket or install a timesert . When changing a head gasket you will have to redo the intake job so you would have wasted all of you money.


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## Bigplanz (Apr 10, 2009)

If you DIY, get an alldata account for your van and study the procedure. It is pretty difficult, so give yourself a lot of time and don't rush. If you have an indoor garage that's preferable. The plastic intake manifold and dexcool antifreeze were IMO a huge mistake. I have a 91 Olds Silhouette and it has the aluminum manifold. 180K miles and that has never been an issue.


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## GrandMasterTech (Dec 3, 2010)

Bigplanz said:


> If you DIY, get an alldata account for your van and study the procedure. It is pretty difficult, so give yourself a lot of time and don't rush. If you have an indoor garage that's preferable. The plastic intake manifold and dexcool antifreeze were IMO a huge mistake. I have a 91 Olds Silhouette and it has the aluminum manifold. 180K miles and that has never been an issue.


Well it is not the plastic that is the problem. We see more intake manifold gasket leaks with the aluminum manifold on the 3.4 and 3.1 liter engines rather than the 3.8 liter with he plastic manifold or what the proper name is plenum. The issues are win the composition of the gasket material and people not flushing their coolant system every couple of years. Trust me I would know I work at a gm dealership and see all of the crap that comes through the door.


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## Bigplanz (Apr 10, 2009)

Although I have no experience with this particular problem, what I have 'heard' is that the plastic manifold expands/contracts differently than aluminum and the gasket fails prematurely. The revised gasket and torque specs are supposed to cure this problem. I have also heard that the dexcool is marketed to have a 100K service life and people think GM is serious so they don't flush their coolant system until the car hits 100K, which is usually 7 or 8 years. By then, of course, the coolant is probably the consistency of warm oatmeal and is clogging the radiator and hoses. I've seen some nasty pictures of this sludge on the Internet. 

I don't know any of this for sure, but this is what I've read/heard around from people supposedly in the know.


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## Swift (Dec 16, 2010)

*GM 3.4 intake manifold coolent Leak*

Re torquing intake manifold 98% of the time well fix the problem


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## TERRY38121 (Dec 5, 2010)

we used to do a malibu and or a apv 3.1 and 3.4 engine plastic gasket it is the coolant eating up the seal that fits around tthe plastic gasket not the plasic is the problem they just leak if done right it should last another 30.000 miles unless you flush out the coolant i mean all of it and use the new style dexcool or the green coolant also like the other tech said do the drive shaft seal when apart only takes a few minutes otherwise if it leaks oil it will be another 3.5 hrs back in the mid 2003 years i had the malubus down to 45 minutes i would leave the back valve cover on they never came back but i had a customer take it to another shop for some other reason they sworn i never replaced the intake gaskets the buearo of auto repair inspected it the field inspector could not believe it that he had worked for buick for over 20 years and never seen it done that way he was on my side he told the customer he did not get charged for the rear valve cover gasket just the front one which i had replaced he told the customer techs are in the business to fix the car right but do it in the fastest way possible even if the book says remove both banks valve covers he said it is fixed isnt it i hate customers like that oh well live and learn i get one like twice a year now if i am lucky they take them to independent shops which do ususally crappy work no factory training there is no special policy or recall but g.m. was offering a check for like from $50.00 and up to like $800.00 depending on the coolant dexcool damage either intake water pump or engine just google it i think they discintinued the program but not sure the aftermarket are plastic as well the 3.8 are now met. repairs and have the right equiptment and nationwide warranty 12utchers out there think they know it all but remember at the g.m. dealer that is all we do is g.mal but it is not the plastic which is causing the leak so it really dont matter i would get the g.m. one they come with new bolts have a g.m. dealer do it i have seen some butchers out there they tthink they know it all but we have the right equiptment and if something goes e thermostat and belt and drive seal wrong we do what ever it takes to make it right plan on spending about between $850.00 to $1500.00 on the high side if you need a water pump and a flush and thermostat that should be done because it is already apart and a fan belt usually intake gasket coolant flush surge tank and cap if corroded or swollen and oil change sorry for the long story but you got me going i miss doing these jobs they were easy to do and paid 7.1 hrs for the intake plus 0.3 thermostat 0.3 oil change 0.6 for drive seal belt overlap no labor already off steam clean 0.5 0.3 for pressure test thats almost 9.0 hrs for a job that could start in morning and take it on a road test at lunce time and have another one waiting right behind it now they just dont come in anymore just vrap that takes 3 days and pays 7.0 hts if you are lucky i will try and send you a bulletin if i can do it thru this site


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## TERRY38121 (Dec 5, 2010)

Swift said:


> Re torquing intake manifold 98% of the time well fix the problem


 hmm i never tried that or seen anyone attempt it just fix it its cheaper than buying another car and have a car payment


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## BigJim (Sep 2, 2008)

I know our Nissan isn't GM but I have a leaking intake also. We have a 2000 Altma with 78,000 and have always taken care of the car as we plan on this being our last car. I did mechanic work back in the 60s but this is beyond me and crawling under a car is out of the question for me. I did the carb cleaner while the engine was running and there was for sure a difference so the intake is leaking air. Will it hurt the engine to run it like this? I know the old cars but these new ones I don't. I have thought about using a high heat gasket sealer and put it around the intake leak which may stop the leak but that is just temporary. Will the sealer work?


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## concretemasonry (Oct 10, 2006)

I had a 1999 Jimmy (4.3L) with 120,000 miles on it then that my mechanic spotted a small leak on during an oil change. I had him fix the gasket problem a day or so later. Since he had everything apart he also threw on a new serpentine belt because he knew I was concerned about it. He spotted it because his wife's car had a similar problem and he had a number of others coming, so he always has a set of the improved gaskets on hand. Two weeks later my wife's Blazer (4.3L) also had a new gasket installed.

The mechanic said that there was a battle between the antifreeze manufacturer that GM installed and GM, so there was no recall and many different models were involved.

The 6-7 hours is on the high side if the mechanic is good and knows what he is doing. I dropped of my Jimmy at 4 PM to have the work done the next day, but the mechanic dropped off my car at 9:00 PM the same day. He had to pick up something on the way home, so he used my Jimmy to go the extra mile, but I had to take him back to his shop, which was 1/4 mile away. - Nice to have a honest mechanic so close.

Dick


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## oregondiy (Oct 24, 2008)

Swift said:


> Re torquing intake manifold 98% of the time well fix the problem


Do not waste your time trying to do this. This absolutely will not fix the problem. Typically these gaskets are falling apart when you remove them to replace them. There is no way that retorqueing is going to do any good.


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## Bigplanz (Apr 10, 2009)

oregondiy said:


> Do not waste your time trying to do this. This absolutely will not fix the problem. Typically these gaskets are falling apart when you remove them to replace them. There is no way that retorqueing is going to do any good.


Yeah, it won't work on an intake manifold gasket. The only application where I knew retorquing did any good was on an old TBI 220 throttle body fuel injector assembly. Sometimes engine vibration would cause a vacuum leak at the throttle body/intake manifold seal and retorquing the mounting bolts would usually seal it. Still, that's way different from a high pressure fluid leak on an an intake manifold. No way retorquing will seal something like that.


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## iamrfixit (Jan 30, 2011)

Swift said:


> Re torquing intake manifold 98% of the time well fix
> the problem


No amount of re-torquing is going to fix this. This is what happens when the gasket fails.

97 Olds cutlass 3.1 with an aluminum manifold, my sons car. Was using a bit of antifreeze, I kept an eye on it for months, it got worse suddenly. Lifters started clattering and oil looked like butterscotch pudding. 

I had never done one but it was not that bad of a job. I am fairly advanced at this kind of thing and have all the tools and a warm shop. Took a couple hours to get to it and maybe 3 to put it back together. Found one lifter was collapsed and stuck, push rod was completely loose. Had to take the lifter apart and clean it up. Lifters still clattered when I got it back together but came out of it after running a few minutes. 

I'm sure I could do a second one a lot faster now! Heard of people paying over a grand to do this job, I used the Fel-pro problem solver gasket set and had about $150 in it with new antifreeze.


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## DangerMouse (Jul 17, 2008)

I have one in the yard with the same problem. You want to come here and do that job again? :laughing: Po)

DM


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## Jackofall1 (Dec 5, 2010)

You might want to call the president of the company, or is that the president of the country, either way they are the same aren't they?


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