The first suspect, even before the thermostat, would be a leaking cylinder head gasket. Your mechanic can perform a chemical test at the radiator to verify that. The test involves drawing air from the radiator, while the engine is running, through a glass cylinder with two chambers partially-filled with a special dark blue liquid. If combustion gases are present, the liquid will turn bright yellow.
Friday, September 19th, 2014 AT 8:07 PM