The head gasket in the 6.0 actually isnt the failure point. the problem is that if the cylender pressures OR the charge of air from the turbo exceed the hold down strenghth of the head bold......the bolt stretches ever so slightly. If it is a head gasket/bolt failure, it will not blow coolant all the time, only under heavy throttle and maybe even only with the chip/tuner in a certain program. eventually it will get worse to the point it overheats and such......but most of the time if it is a headgasket failure it will have intermittant overheating along with coolant purge. an EGR cooler is much more consistant with the coolant purging........Marc