I have had the intake manifold gaskets replace by the dealer twice since the vehicle was new. I figured this time I'd take a stab at it since they don't seem to have a fix that last more than 80k miles.
I purchased all the gaskets associated with the upper and lower manifold and proceeded to get the all the stuff out of the way and removed the manifolds. When I pulled the lower manifold I notice that the dealer did not use the two small rubber gaskets that seal the front and the back of the lower manifold to the block but put a huge bead of rtv in place of the gasket and set the manifold down on that. Does anyone know if this some fix GM came up with or was this the dealer mechanics idea of automotive re-engineering?
The two small gaskets don't seem to be part of the chronic coolant leak problems these engines have so I can't imagine why they would have not been used.

 

Welcome to the forum.

IIRC, they have used a RTV bead for the end rails for quite some time now. But the gaskets sets still include them. The problem was the rubber gasket would squeeze out, especially if both surfaces weren't very clean or if incorrect machining had been done to the block and/or heads.

 

I'm in the process of cleaning all the surfaces and testing the fit-up prior to actual install and I did notice the gaskets seemed to be problematic at the interface between the head and the "end rails" (now I know what to call them). I'm going to give the gaskets a try and see if they sit okay. If not it'll be RTV. Thanks for the reply...

 

Are you using new intake bolts? Did the dealer? As I recall, they are torque to yield bolts and are supposed to be one use only.

 

I reused the bolts I pulled out. So it's already too late for this iteration.....
Your comment made me go back to the service manual and make sure I didn't miss that in the process. I have the factory manual and it doesn't mention anything about single use for the intake bolts but it does make that distinction for the head bolts..Nevertheless that doesn't necessarily mean their not, the manual has many discrepancies and obvious errors and omissions...

Thanks for the heads up....

 

I have a 97 with the 5.7 motor and the lower intake bolts are supposed to be replaced if removed, hopefully goes good with yours since you did reuse them.

 

My 7.4 Suburban has done fine over the last year or so with the reused intake bolts.. I just did my 5.7 and used new bolts.....It has only been a couple of months but so good so far...At the same time a swapped out the SCPI with the Delphi MPI. The truck runs better now than it did the day I drove it off the lot in 99.
I also swapped out Dexcool for traditional green in both after a good flush. No problem there either....