Another trick is to place a few aspirins on the thermostat once you pry it open. They will melt away once the water gets to them. The drilled hole is about the best way since you have to remove it for either tip. Once its out, hang it in a pan of water on the stove and find out why is letting the engine run so cool, if it really is that cool.
Let it seek its own coolant level, once down a ways, it should quit spitting it out. mine used to like to be right at the top of the fins, any more and it push it out when hot.
Are you using a pressure cap on a open system? Try putting a overflow bottle on and catch what comes out so it can suck back in what it once after it cools off.
Joe
