Jim Grant's Tech Tips
'95 Ford Mustang GT, Slow Overheat
own a '95 Mustang GT and have had a cooling problem for a few months.
The car will slowly overheat at a stand still. The fan will come on but
sometimes it doesn't seem to cool the car enough and it will soon overheat.
When I'm driving the car it actually runs too cold and never gets into
the normal range. Being that it is wintertime it's not too bad but when
warmer weather gets here I probably won't be able to drive the car. I
have changed the thermostat, flushed and refilled the radiator and changed
the belt, but to no avail. I've been racking my head for months.
inspection of the water pump and cooling fan is in order. Water pumps
have impellers that can wear in a manner that reduces coolant flow at
the lower engine speeds of in-town driving and stop and go traffic. At
highway speed the engine drives the water pump fast enough to cover the
problem. As for the cooling fan, just because it turns on doesn't mean
it's doing its job. As an electric cooling fan motor wears it can lose
speed/RPM. The reduced speed means less airflow over the radiator to cool
the coolant. You have 2 areas to check out before the summer heat hits.