Description
If my truck is over heating and I turn on the heater and it cools down what could be my problem?

Explanation & Answer

Hi,
I would suspect the following
1. Bad or failing thermostat
2. Weak or failing Radiator fan( if electric)/ fan clutch
3. Air pocket in the system. If your car has a bleeder, warm up your car and open the bleeder to let the trapped air escape. Most cars are not equipped with the so called bleeder.
