If the thermostat is new and installed correctly, not backwards, possible to do on some vehicles, I suggest watching the coolant level to see if it drops. I would also check out the plugs to see if they are burning correctly. Note if you smell anitfreeze in the plug hole. Is there any coolant on the plug? Do you smell any different smells out of the exhaust. With the radiator cap open and the engine nice and warm, is there any bubbling in the radiator? After all that you have done, I suspect that the engine has gotten very warm at one time or another and the head is warped causeing the gasket to leak.
Let me know what you find on those questions.
Monday, January 8th, 2007 AT 9:43 PM