3800 Engine Problem Question

[Jolly_John]

Hi, Gang. My son-in-law (and his mechanic) thought he had experienced the typical upper intake manifold coolant leak on his non-supercharged 3800 engine. He had the plastic upper intake manifold and gasket replaced....but the coolant leak still exists. The engine is consuming about a half a cup of coolant every couple of days, plus there is a little external pooling of coolant between the upper intake manifold and the engine head (the head closest to the front of the car).

The lower intake manifold gaskets were NOT replaced when the upper job was done, and the mechanic indicated that might be the source of the ongoing problem. The mechanic also stated the lower intake manifold could be warped. That was just a comment though, not based on any troubleshooting.

My questions for you all: In searching the internet, I found lots of info about this GM 3800 engine problem. However, the possibility of a warped lower intake manifold was never mentioned. Does anyone have a comment about the liklihood of this (the car has never been overheated)?

Second, if the lower intake manifold gaskets are bad, how in the heck would that cause the coolant pooling we're seeing up on top between the upper intake manifold and the one head. I guess I don't understand the theory on that.

Any comments would be appreciated. Thanks, John

[tim63riv]

John,

I take it your son's mechanic is not at a Buick dealership. There has been a lower and upper intake manifold released that should solve his problems. The repair isn't cheap but it is effective.

I have seen a coolant leak between the throttle body and the upper intake that would puddle in the the area that you mentioned, usually a revised throttle body to intake manifold gasket will clear that up. I think the original is gasket is red and the updated one is blue.

HTH,

Tim