Why does the car fan keep running?

[AliyahMarie]

If you notice the radiator fan running immediately after turning off the engine, you can wait for a while. This is because the water temperature in the radiator decreases slowly, and the cooling fan may continue to operate for some time before stopping when the engine is just turned off and the water temperature hasn't dropped yet. However, if the fan keeps running even after the car has completely cooled down, it might indicate a fault in the cooling fan assembly or its wiring. More information about the car's electric fan is as follows: 1. Working principle: The car's electric fan is controlled by a thermostat. When the water temperature rises to the upper limit, the thermostat activates the power supply, and the fan starts working. Once the water temperature drops to the lower limit, the thermostat cuts off the power, and the fan stops. 2. Working requirements: The electric fan motor draws a high current during operation, which demands higher specifications for the wiring used.

[NathanFitz]

I just bought a new car and found that the fan keeps running non-stop, usually because there's a problem with the cooling system. The coolant level is too low, causing the engine temperature to rise excessively, so the fan works overtime to cool it down. Sometimes, the coolant temperature sensor is faulty and gives incorrect readings, causing the fan to default to running at full speed without stopping. A stuck relay is also a common issue—once the circuit shorts, the fan runs continuously like clockwork. In my previous car, the fan running for too long drained the battery severely, making it difficult to start. I recommend first checking if the engine bay is hot, inspecting whether the coolant reservoir level is normal, and also seeing if the air conditioning is on, which adds extra load to the fan. If the fan keeps running without being fixed, the engine can overheat and damage the pistons or cylinder head. Always keep an eye on the temperature gauge while driving to avoid this issue, and if it persists, get it repaired immediately.

[JuniperFitz]

As a driver with over a decade of experience, I understand that the issue of a continuously running fan is usually caused by a malfunctioning signal system. The fan's mission is to regulate engine temperature, but faulty sensors can mislead it into running at high speeds constantly, especially on hot days when the fan works harder. Additionally, turning on the AC will also cause the fan to speed up to assist with cooling. This constant spinning consumes a huge amount of power, and the battery may not hold up, potentially preventing the car from starting. I usually test the fan module for abnormalities after the engine has cooled down and check if the relay contacts are sticking. Long-term neglect can increase fuel consumption and accelerate component wear. It's best to use a simple diagnostic tool to check for error codes or directly consult a professional mechanic to inspect the entire cooling circuit for safety.

[DeTyler]

If the fan keeps running non-stop, it's likely due to a faulty sensor or relay. A malfunctioning coolant temperature sensor can cause the fan to run erratically; a bad relay keeps the circuit constantly closed, preventing the fan from stopping. Simple checks: if the fan still runs after the engine cools down, there's an issue; check if the fuse is blown, and try unplugging the sensor connector to reset. If noticed while driving, stop and turn off the engine to inspect, to avoid battery drain or engine damage. Timely repair is crucial for safety.