Actually it was driven without coolant, ONLY the overflow had anything in it. I'm not sure why it didn't get sucked into the radiator...kinda glad it didn't, considering how nasty it is in the overflow. I had to put about 4 gallons of coolant in the radiator.

1/3 of the engine's cooling comes from oil, and the oil wasn't low at all. Probably the only thing that saved it from a catastrophe. I imagine it's not as delicate as a new car's engine either.