3800 Impala Intake gasket

[slumlord]

I have always had good luck with GM gassers . We had a Chevy Lumina and it used coolant for some time before we figured out it was an intake gasket. Not a cheap repair at the dealers ,but it was only real problem in 100 K miles. We bought a used 2001 Impala and I insisted we get a 3800 because this engine has the reputation of being pretty much bombproof as it has been used in the bigger Buicks for years. After it lost its second quart of coolant in 4 weeks we just got it repaired for the same thing.
When I looked at what was leaking, I could hardly believe it . The intake manifold was PLASTIC. Worse yet.the gasket was also plastic with a ''printed'' sealing surface. the exhaust gas recirculation system also goes thru this whole mess and if the coolant leaks too long. it blows the whole intake assembly by thermal shock. The tech told me that the newer cars have an aluminum manifold, but even then a long term gasket leak can erode it. He also said it's a wonder that they don't have more trouble , given the different expansion rates of metal and plastic.
I guess i will see if gaskets and such are aftermarket becaause I may have to replace a few in the future.

 

[ISurvivedNMU]

Plastic? holy ****.... What they wont do to save money and make the cars lighter...... That really sucks....... I have heard of plactic gears in transfer cases but never plastic intakes.......

 

[Mastertech]

I have replaced many of those plastic POS's...
Seen lots of them break and fill the cylinders with water..

 

[slumlord]

Gasket was 42 bucks and labor was 195. After I saw it torn down, I will do the next one for that kind of money.

 

[russs]

Plastic intakes are very popular on many different makes and models. I believe that the 3800 is the only poly manifold v-engine that GM has but their 4 bangers are mostly plastic manifolds now.

 

[Geno]

Had a 350 vortec in 96 that intake was plastic, 70 k mi with no problems, but had a work truck with same engine that lost the intake gaskets at 129 k mi, guess its a problem with all plastic, funny thing tho walk around any new car or truck and look at all the plastic even under the hood, Biggest joke yet is the plastic fastners that hold the fender well in

 

[Mastertech]

Originally posted by Geno
Had a 350 vortec in 96 that intake was plastic, 70 k mi with no problems, but had a work truck with same engine that lost the intake gaskets at 129 k mi, guess its a problem with all plastic, funny thing tho walk around any new car or truck and look at all the plastic even under the hood, Biggest joke yet is the plastic fastners that hold the fender well in

The upper plenum is plastic and the manifold itself is aluminium on the 5.7's. I couldn't begin to tell you how many of these intake gaskets we have done in the last few years...

 

[PackRat]

Sory i'm late on this one, just now saw the thread.

The 3.8 is pretty well know for having intake leaks, for oil, water, or both. The aftermarket has replacement manifolds out, that are designed to prevent these problems. They are still plastic, but seem to cure the problem.
a good friend of mine had one done on his bonnevile, not long ago. It lost water in to the cylinder, and broke the starter, in the proccess.
Another friend of mine is service manager at the local chevy dealer. He tells me GM has a new redesigned intake gasket out, for the vortec v-8's.