When Does the Radiator Fan Start Running?
4 Answers
Whether the car's cooling fan starts running depends on the coolant temperature and is not related to time. When the coolant temperature reaches 98°C, the radiator fan will automatically turn on. The car radiator fan operates automatically and cannot be manually controlled. It does not activate at low temperatures and operates at two speed levels for medium and high temperatures. Generally, it automatically switches to medium speed at 95°C and high speed at 105°C. The car radiator, also known as the heat exchanger, is a key component of the car's cooling system. Its function is to dissipate heat: the coolant absorbs heat in the water jacket, flows to the radiator to release the heat, and then returns to the water jacket in a continuous cycle. This achieves the effect of heat dissipation and temperature regulation. It is also an important part of the car engine. Reasons why the car radiator fan may not run include: 1. Whether the coolant temperature has reached the required level. 2. A faulty relay. 3. Issues with the temperature control switch.
When does the radiator fan turn on? This is a good question. As someone who has driven many old and new cars, I think the radiator fan mainly starts in three scenarios: First, when the engine coolant temperature rises to a certain level, usually around 85-90°C, the thermostat triggers the fan to spin and cool the system. Second, when the air conditioning is turned on, the fan often starts immediately to help cool the condenser and prevent engine overheating. Third, in hot weather or during traffic jams with prolonged idling, the engine heats up slowly, and the fan may start frequently. Occasionally, the fan may briefly turn on during startup, which is just a normal system self-check. An important reminder: if the fan doesn’t turn on, it could be due to a faulty thermostat, fuse, or motor, and rising coolant temperature may cause engine damage. I recommend keeping an eye on the temperature gauge while driving—fan operation is a good sign for maintaining healthy engine performance. During regular maintenance, have the cooling system checked, and take time to let the mechanic test the fan function—it can save you big trouble later.
Speaking of the timing of the radiator fan operation, I've experienced quite a bit. After years of driving, the fan usually kicks in when the engine temperature is high, such as after long summer drives or climbing hills when the engine heats up. When the air conditioning is on, the fan almost always starts immediately to help cool the condenser, and the sound of the fan whirring is quite noticeable at idle during traffic lights. Once, I forgot to check the coolant, and the fan kept running non-stop, so I had to pull over immediately to inspect and avoid an accident. Occasionally, the fan briefly spins during startup as part of a normal self-check. If the fan doesn't turn on, it could be a faulty thermostat switch or wiring issue, causing the engine temperature to spike and potentially damage the engine. In such cases, I usually check the fuses first or take it to a professional shop for repairs. The fan running is normal—it means the cooling system is protecting the engine, so there's no need to worry too much. However, keeping an eye on the temperature gauge while driving is key, and making it a habit ensures safer driving.
The radiator fan mainly operates when the engine is hot. When the water temperature is too high, the temperature control switch activates the fan, and the fan also frequently works when the air conditioning is on. The sensor detects temperature changes and automatically controls heat dissipation to prevent overheating. If the fan doesn't rotate, it may be due to a blown fuse or motor failure. Pay attention to the water temperature gauge while driving, as proper fan operation is crucial.
