Reply to "What the heck just happened?"

One way to tell for sure. Start up the engine with the radiator cap removed. Rev it up a few times. If you have a head gasket leak, you will start bubling out the radiator cap as the combustion gas leaks into the water jacket.

And no Jack, you dont always get coolant in the oil with a head gasket leak nor do you always get white smoke. It takes TONS of coolant to get white smoke and water in oil. You typically only see that kind of leak on race cars where the gasket blows badly and rapidly.

I have blown head gaskets from age on 4 different cars (2 302s, a 3.8 and a 1.8) and none of them had smoke or water in the oil. The only tell tale sign was a missfire at idle once warmed up.