Follow the radiator hoses (there's two). One goes to the water pump, the other to the thermostat.
The quickest way to confirm the thermostat is operating is to feel the upper and lower radiator hose as the engine warms up. If one is hot and the other is not, then the thermostat isn't opening.
Also, just because there's no coolant in oil doesn't mean the head gasket isn't blown. Depending on where the gasket blew, the coolant could leak into the oil, or exhaust gases could leak into the cooling system on the power stroke.
As the engine heats up, the head and block deform slightly at different rates. This causes a tiny leak past the gasket. It gets worse as the engine is reved up under a load. But usually the coolant would leak back into the cylinder once the engine is shut off. The the coolant will sit in that cylinder and burn off the next time you start the engine.
Friday, February 25th, 2011 AT 2:12 PM