I know it would take a great deal of effort to accomplish this, but for a car that already has over 100,00 miles on it, what does it take, or what kind of driving would it take, to cause this to happen?

Anyone know :confused:

Has the engine in question already blown a head gasket? The most likely cause would be overheating. Most head gaskets today will last forever as long the engine is well maintained and driven under normal conditions. If the engine is ran hard and allowed to run hot, then you can blow a head gasket, among other things.