When does the car engine fan turn on?
2 Answers
The car engine fan operates based on coolant temperature. Generally, when the coolant temperature reaches approximately 80 to 90 degrees Celsius, the fan starts working. The computer controls its operation upon detecting elevated temperatures to achieve engine cooling. When the coolant temperature returns to standard levels, the fan stops working to maintain normal engine operating temperature. Specifically, when the coolant reaches 95°C, the fan activates and runs at about 1,600 RPM. At 105°C, the fan speed increases to approximately 2,400 RPM to enhance cooling efficiency. Whether the fan operates at idle depends on coolant temperature - it doesn't immediately activate upon cold start idling since the coolant hasn't warmed up yet. Typically, it takes about five minutes for the fan to start running at idle.
I know this well. The engine fan works like a thermostat—it doesn't spin all the time. If the coolant temperature hasn't reached the threshold, it stays idle. You'll notice it starts whirring when the temperature gauge approaches the red line or during summer traffic jams. It also kicks in when you turn on the AC, as the compressor heats up the radiator. During cold starts in winter, you'll hardly hear it. Sometimes, it keeps spinning for a while even after you turn off and lock the car, which helps cool down the turbo. As long as it's not completely dead or spinning nonstop, it's operating normally. But if the engine overheats and the fan still doesn't respond, it's time to check the wiring, thermostat switch, or fan motor.
