Q: engine fan noise

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A fan comes on sometimes and runs continuously after engine temp gauge reds just below half mark.

My car has 147000 miles.
My car has an automatic transmission.

The engine should always operate in the "normal" range as shown on your temperature gauge. If the temperature is too high, shut down the engine as overheating can have disastrous consequences (costly repairs). If too low, that is not an emergency (no need to shut engine off) but low temperature operation is inefficient and over an extended period of time a low engine operating temperature will cause problems such as engine deposits. The radiator cooling fan is designed to cycle on and off, with the duty cycle dependent on engine load, driving conditions and ambient temperature. The cycling rate and duration is controlled by a cooling system temperature sensor. If the fan operation seems prolonged compared to past experience with the car, the circuit and the sensor can be tested to determine if they are operating correctly.

If you desire that the cooling fan and circuit be evaluated by a certified Mechanic, dispatched by YourMechanic right to your location, please request an engine cooling fan circuit/thermo switch diagnostic and the responding certified mechanic will get this issue investigated and resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

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