3.8 GM intake manifold replacement/instructions

[mross66]

i have seen so much "stuff" about how to do this job. could someone PLEASE direct me to ONE place that has all the info regarding this procedure...its a 3.8 w/ the plastic upper....

[BNaylor]

Welcome to AF.

What year is your Grand Prix? Just the UIM plenum, LIM or both?

[mross66]

Originally Posted by BNaylor

Welcome to AF.

What year is your Grand Prix? Just the UIM plenum, LIM or both?

my gp is a 2002 3.8L. there is coolant starting to seap into the oil and dealer says it is the upper intake and gasket that needs replacing(as this common problem continues). some things ive read say to replace the LOWER gaskest while everything is apart...???not sure if i really should or not. i am looking for some good instructions with pics possibly, i have a haynes manual but we all know how that is....thanks for any info you can give.

[BNaylor]

Since you have a '99 and up the UIM plenum gasket is possible. The lower years ('98 and under) suffer from EGR stovepipe meltdown causing the coolant consumption which requires replacing the UIM plenum. We recommend that the LIM gaskets are replaced since they are an issue and could be the cause of the internal leaking. To start it is best to remove the UIM and perform an inspection.

Just send me a PM message with your regular email address and I'll send you a PDF file that covers it in general.

[wlkjr]

I'd definitely do the lower while it's torn down. It won't cost that much more and it will be less aggravation later on.

[76vette]

Originally Posted by mross66

i have seen so much "stuff" about how to do this job. could someone PLEASE direct me to ONE place that has all the info regarding this procedure...its a 3.8 w/ the plastic upper....

I was wondering if you have coolant in the oil/cylinders? I had this problem with my wifes 98 grand prix 3.8 liter,basically the same engine.I passed a car running it hard the transmission didn't shift and warped the plastic plenum internally. I replaced the UIM and LIM gaskets,but the mistake I made is I ran it too long with coolant in block. The engine seized a bearing in about 5,000 miles after I fixed it and through a rod through the block.