What is the reason for the car fan not rotating at low speed but rotating at high speed?
1 Answers
Car fan not rotating at low speed but rotating at high speed may be due to a damaged thermostat, abnormal circulation of the vehicle's cooling system, causing the temperature control switch to malfunction, which can also lead to this situation. The last possible cause is a faulty engine coolant temperature sensor. Below are additional details: Principle: When the coolant temperature is below 70 degrees, the thermostat remains closed. At this point, the engine's cooling system only has a small circulation loop, without a large circulation loop. This means the water from the engine's outlet pipe passes through a small bypass pipe directly into the cylinder head for internal circulation. Specific reasons: At this stage, the coolant does not pass through the radiator. As the temperature continues to rise to nearly 80 degrees, the thermostat gradually opens until it is fully open. Then, the engine's coolant flows through the main outlet pipe to the radiator before entering the cylinder head for large circulation. If the engine temperature continues to rise, the temperature-sensitive switch installed on the thermostat cover or radiator will activate the fan's low-speed switch, causing the fan to rotate at low speed and draw air from front to back for cooling.
