Long story short I had a bent rod and bad head gasket replaced in my 6.5. Before I brought it in, if you got on the gas with the heat on the interior would reek of antifreeze. Obviously this point to a problem in the heater core correct? There was excess pressure in the coolant system that would overflow the surge tank. Do you think the excess pressure damaged the core? Or is there for some stupid reason a relief valve in the core. LOL Should I have the core checked out?