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Q: Overheating issue, when heater is on its normal temp. but if heater is off it begins to overheats, until heater is turn on again.

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When driving, car over heats, but if I turn heater on, temperature eases back to normal, and is good to go unless I turn heat off again. Even when in idle doesn't run hot with heater on, but if heater is off it over heats.I put new water pump thermostat radiator degas bottle and cap heater control valve and bled it several times

My car has 200000 miles.
My car has an automatic transmission.

It sounds like your engine might have a restriction in the cooling system. If the cooling system has a restriction that prevents its flow, this will cause the engine to get hot. The heat is dissipated from the cooling system by means of the radiator.

When a restriction exists sometimes the radiator alone is not enough. The heater core is like a small radiator inside the dash and is also another means of dissipating the heat from the cooling system. So essentially when the heat is on you are introducing a second radiator into the system which will help to cool the engine down.

In order to get this fixed, consider YourMechanic, as one of our mobile technicians can come to your home or office to diagnose the overheating issue firsthand and help you make the necessary repairs.

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