When driving car over heats, but if I turn heater on, temperature eases back to normal, and is good to go unless I turn heater off again. Even when in idle doesn't run hot with heater on, but if heater is off it over heats.I put new thermostat radiator and yes I know what about the water pump well I want to see before I buy this expensive part see what else it can be before buying it. thank you!!!!

 

Are your cooling fans running when the car is overheating at idle?

If your car is equipped with A/C. This is how the cooling fans operate.

Generally, both cooling fans (radiator fan and A/C condenser fan) should be running at the same time; high coolant temperature or A/C is on.

When coolant temperature is above 206_F (97_C), both cooling fans should run. (High speed)

When A/C is on, both cooling fans should run. (Low speed)
When A/C is on and if the refrigerant pressure rises above 1520 kPa(221 psi), both cooling fans should run. (high speed)

 

Yes both fans do run i also forgot to mention i replaced the a/c fan and temp sensor as well.