F150 5.4 triton heater blows cold and engine temp gague goes up
We have a 2001 f150 5.4 triton with 115,000 miles
on it. Bought it about 9 months ago so we don't
know the history on it. The heater will work fine
until about 5 minutes of driving it, suddenly the heat
starts blowing cool air and the engine temperature
gauge skyrockets. I pull the truck over and turn it
off, rest it for a minute or two, turn it back on and
the temperature is normal again and the heat is
working properly. Had it at a shop who ran all kinds
of block tests on it, it is definitely not a head gasket
problem. Replaced the thermostat and still have the
problem.
