I've been fighting with my thermostat housing leaking ever since I replaced the thermostat. I thought the housing itself was bad, so I bought a new one, still leaks. I've tried putting on a new gasket with no RTV, it leaks. Then I tried putting RTV on either side of the gasket, still leaks. Then finally I sandwiched the gasket in RTV and it still leaks. I am using gray RTV. anyone else have this issue? When new gasket is put on both surfaces are clean and free of old gasket material, etc. I've done many thermostats in the past, never had one leak!

P.S. 92' 2.3L

 

Heres a tip: when using RTV don't use a gasket. The RTV is a gasket itself.

 

I thought about that but the PO had a gasket with black RTV in there. So I am trying to decide whether I want to try that route or just black RTV without a gasket. Either way it is annoying me, this motor is free of any leaks except this, even the oil pan gasket doesn't leak a drop or anything(knock on wood).

 

I've done it without the gasket twice with blue and red rtv. Never a leak after each time.

Make sure that you don't tightened it on, but wait a half hour then tightened the bolts

 

I'll have to try that, thanks!