The cooling fan is a vital part of a car’s cooling system. It is sited just in front of the car’s radiator, and is electrically powered.
A cooling fan in a car is activated by two means – either by the thermostat in the car’s cooling system, or by an electronic system that senses when the coolant is too hot and switched on the fan through an electrical relay switch.
A cooling fan tends to be dormant unless the car is stationary or the temperature is excessively hot.
In either scenario, not enough cooling air is being forced through the radiator, so the temperature goes up, and the fan is activated to increase the amount of cooling air being fed through the radiator element.
However, listening out for the cooling fan can be a quick and easy way to tell if your car’s cooling system is working at peak efficiency or not
If you hear the fan being activated on a cool day, or if the fan is in operation after even a short run, there’s a good chance that the level of coolant in your car has dropped, or there’s a fault elsewhere, such as with the thermostat.
It’s worth letting the car’s cooling system cool down so you can accurately check the level of fluid in the expansion tank – it should be between and H and L mark on the side of the tank.
If the level of coolant is low, it’s worthwhile checking the state of the car’s rubber cooling pipes. These lead from the radiator to the expansion tank and from the car’s engine to the radiator.
Vibrations caused when the car is moving can make the pipes wear if they happen to be rubbing against other components, and if there are any bulges in the pipes you should replace them straight away and bleed the system.