When Should a Radiator Fan Start?

A radiator fan plays an important role in keeping a vehicle's engine cool. However, a broken fan could be mistaken for a fan that just hasn't kicked in yet. This is one reason why information on when a radiator fan is supposed to start can be beneficial to vehicle owners.

Time Frame

The temperature will determine how long a radiator fan should be on. The switch functions are sensitive to temperature, 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 approximately 200 degrees Fahrenheit.


A radiator fan uses its fast spins to draw in air from outside. The air in turn cools the antifreeze that is circulating inside the radiator, keeping the vehicle's engine cool. Some vehicles are equipped with an extra fan for more efficient cooling.


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