When Does the Radiator Fan Start Running?
2 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.
