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
Sounds like the cooling system needs to be purged from air pockets, or the coolant is just low.
Pressure test was done overnight and found no problem. Have " burped" the system twice now,
And of course the radiator has ben checked I bet. Maybe you got a bad thermostat. You could take it out put it in a pan of water with a thermometer to see when it opens.
With the thermostat going through the roof at the same time the heaver stops blowing hot air would seem to indicate a possible blockage. Sounds like water is not circulating through the heater core at times, and at those times the temp rises. Sure the pump is OK?
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