I just had the cylinder heads replaced on my Subaru Impreza and now the engine heats up very quickly but doesn’t overheat. What could be the problem?
Head gasket put in wrong, maybe. That would allow exhaust gas to get into the cooling system. Possibly sealing itself when the engine warms up. Take off the radiator cap when the engine is cold and look for bubbles as the engine is running. Also ask the mechanic to recheck it.
Ask a DIFFERENT mechanic to check it. See if Car Talk has a mechanic in your area that has been recommended and take it there. You are talking about a lot more money if your engine seizes.