What is the problem if the car cooling fan keeps running?
2 Answers
It is normal for the car cooling fan to keep running. Here are the detailed reasons: Fan delay shutdown is for cooling: When the engine is running, the temperature distribution in the entire water channel is not uniform, and there are local high-temperature spots. When the water pump stops running, these heat cannot be dissipated, so the fan delays shutdown to cool down, which is a normal phenomenon. The electric fan is controlled by sensors: Although the car is turned off, the temperature has not yet dropped. The electric fan is controlled by sensors. Sometimes in summer, when the car is parked in the sun, the electric fan will rotate even if the car is not running, as long as the temperature reaches a certain degree. This situation is normal. If you don't want it to rotate, you can turn on the ignition switch after turning off the car, but do not start the engine, just connect the power supply, and the electric fan will automatically turn off.
With over a decade of driving experience, I can say that a constantly running fan is usually caused by a stuck thermostat. The thermostat acts like a valve controlling coolant flow—if it fails and gets stuck in the open position, the system keeps thinking the engine is overheating, so the fan keeps spinning nonstop. This issue is common in summer, especially in older cars where the thermostat may corrode and cause trouble. Not only that, but a continuously running fan drains the battery quickly, making it harder to start the car after a few days, and it can also lead to higher coolant temperatures, increasing engine strain. For routine checks, start by inspecting the coolant level—if it's low, there might be a leak that needs fixing. Regularly replacing the coolant helps prevent corrosion and extends the thermostat's lifespan. If you spot the problem, don’t delay—get a mechanic to replace it, and you’ll save yourself a lot of hassle.
