3XBLACK67
Active member
A small amount of anti-freeze leaks from the bottom of the thermostat housing on my 427/390, where the housing joins the intake manifold. I have tried different gaskets and stop leak products with no luck. Today I took the housing to a shop to have it machined flat, in case it had warped a bit. While getting it ready to re-install, I noticed that in one of the two bolt holes, there is a rubber plug with threads for the bolt. The rubber looks like it has disintegrated a bit. Could this be the cause of the leak? If so, can the rubber piece be replaced? I don't want to replace the housing with a new one because this one appears to be original, with the GM logo and correct part number at its base.