I am going to look at a '95 2500 4x4 ext. cab long bed, A/T 140K 6.5L diesel. The guy wants $1500. He said it has a blown head gasket. If the guy ran the truck like that will it kill the motor? Or, do these hold up, and essentailly I would just need to do a head gasket job? I am a mechanic with alot of gas and cummins experience, but I have never encountered a 6.5 or any diesel blown head gaskets. Are these common on these motors?