1998 Chevy Lumina head gasket

i have a 3.1 lumina 98 i noticed it was running hot so i shut it off checked the oil cap then i noticed that there was coolant mixing with my oil so i though head gasket so i started tearing down the engine well finally got both heads off there not warped nether head gaskets were broke but there was coolant on the piston what im asking is that can a gasket be blown but be whole if not what is wrong with my car