When Is a Radiator Fan Supposed to Start?

by Marcus Baker
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A radiator fan has an important role of keeping a vehicle's engine cool. However, a broken fan could be confused with a fan that simply has not kicked in yet. This is one reason why information on when a radiator fan is suppose to start can be beneficial to vehicle owners.

Time Frame

Temperature will often determine the time that a radiator fan starts up. A temperature-sensitive switch functions to turn the fan on and off periodically. Radiator fans are designed to start when the temperature of the engine coolant reaches around 200 degrees Fahrenheit.


A radiator fan uses its fast spinning blades to draw in outside air. This in turn cools the antifreeze and water that's within the radiator, which keeps the vehicle's engine cool as well. 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 the fan fails to start. This often causes individuals to buy a new fan motor, when the true culprit could instead be due to a non-working fan motor module.

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