What Temp Should My Fan Kick In?

Your radiator fan should kick in at about 200 degrees Fahrenheit. If you notice your vehicle is overheating or at the very least running hotter than it normally does, listen for the fan to see if you can hear it. If you can’t and it doesn’t turn on eventually, Doc Motor Works can repair or replace it to keep your engine’s cooling system operating at peak efficiency.

Fan Trigger

The engine temperature should trigger the fan to turn on. It will also turn the fan off once the engine has cooled to under 200 degrees. You may have heard of a part called the radiator fan switch or temperature fan switch. This is linked to a thermostat and works much like your home’s HVAC system. Should either of these parts fail – the thermostat or the switch – your radiator fan will not turn on or off and this spells serious trouble.


The reason why this spells serious trouble is the radiator fan keeps your engine cool. Yes, the radiator and coolant inside of it also prevent the engine from overheating, but the fan, too, plays a crucial role. You may have noticed your vehicle’s grille has holes or slats in it that open directly into the engine. This is because the engine needs air to keep it at the optimal temperature. The grille cannot draw enough air through most of the time, which is why you have a radiator fan.

The fan’s job is to keep the radiator fluid/water mixture cool while you drive. If, for example, you’re stuck in traffic, you will not have enough air circulating over the radiator to cool the fluid and engine. The fan turns on to circulate additional air. You can figure out the rest. This comprehensive cooling system prevents the engine damage associated with overheating, and as an aside, the fan itself can also fail.

Don’t Assume That’s the Case, Though

If you don’t hear your fan turning on, don’t assume that’s the case, however, and rush out to the auto parts store to buy a new one. Many people blame the fan motor as the reason why the fan doesn’t run, but as we discussed above, it could be the thermometer or fan switch. If your fan isn’t running, or it doesn’t turn on until it’s too late, it’s best to have the radiator system inspected. This ensures the vehicle receives the proper diagnosis and repairs.

Call Doc Motor Works at 815-577-3893. We serve customers in Plainfield, IL, as well as Shorewood.

Call Doc Motor Works at 815-577-3893 for an appointment today!