How Often Should the Radiator Fan Turn On?

The radiator fan plays an important role in maintaining a vehicle's engine. However, a broken fan could be mistaken for a fan that simply hasn't started. This is one of the reasons why information on when a radiator fan should start can be beneficial to vehicle owners.

Time Frame

Temperature determines how long a radiator fan should be on. The switch functions are temperature sensitive. The switch is responsible for turning the fan on and off periodically. The radiator fans are designed to start when the engine coolant temperature reaches 200 degrees Fahrenheit.


A radiator fan sucks in outside air with its rapid revolutions. The air in turn cools the antifreeze circulating through the radiator, keeping the vehicle's engine cool. Some vehicles are equipped with an additional fan for more efficient cooling.


A common misconception is that a cooling fan motor is always the problem when the fan is not working. This often leads people to buy a new fan when the real problem could be with the fan motor module.