I can't help but wonder if the blown gaskets are more a function of the engine with an overheat history or if this is truly "just" a coolant issue. We are all very well aware of the achilles heel radiator, valley coolant leaks, and potentially heater T's. All of these, left unchecked, will result in an overheat. Expansion during an overheat could force coolant into places to normally doesn't go and start a slow degradation of the materials in the head gaskets.