Hello everyone, i just bought a 1998 F150. They told me that the heater core needs replacing, but doesnt leak. Ok i figure that it is something else......heater core does not leak. Both hoses to heater core get hot, telling me that it is not blocked. I figure that the thermostat is stuck open....what do you think....thanks in advance.....Don

 

Well guys I replaced the thermostat, and still no heat......when engine gets hot i put the heat on and it is hot for about 30 seconds.......what could it be...