Will a bad head gasket show up as low compression in a cylinder on the N*? I bought a used one for my 94 STS, and while the compression test shows great, I'm worried about the headgaskets failing at some point in the future. Thanks!
I doubt it. It would have to be one hell of a bad gasket to do that. I think the only way to tell is pressurize each cylinder and see it it holds air for :10-:15 minutes.
A really bad gasket might show up . I set the engine up on the stand pluged all but the highest coolant hole filled with water and air pressure tested each cyl in the firing order (fewer turns of engine w/o oil pressure) to check for gasket leaks .