What are the reasons for a car's cooling fan not having a low speed?
2 Answers
There are several reasons why a car's cooling fan may not have a low speed, including the operation of the electric fan, the opening of the thermostat, and the phenomenon of water pump cavitation. Below are the relevant explanations: 1. Whether the electric fan is working properly: Normally, the electric fan has two speeds. One is the low speed, and the other is the high speed. The high speed usually operates when the air conditioning pressure is too high or when the engine's coolant temperature reaches 103 degrees Celsius. 2. Whether the thermostat's opening is insufficient: If the thermostat's opening is too small at normal temperatures, it will slow down the circulation speed of the engine's coolant. This can lead to high coolant temperatures at low speeds. 3. Check if the water pump is experiencing cavitation: The water pump impeller is made of plastic. If the shaft part cracks, it can cause cavitation when the coolant temperature is high, leading to elevated coolant temperatures.
I remember once my car's cooling fan suddenly stopped working at low speed, causing the engine to overheat. After checking, possible causes included burnt fan motor coils leading to low-speed failure, or aged wiring causing short circuits or open circuits. Blown fuses are also a common issue, especially when excessive current interrupts the low-speed circuit. If the control module malfunctions, such as a failed temperature sensor, the fan won't receive low-speed signals. I recommend starting with simple checks - inspect the fuse box and fan connectors for looseness. Always monitor the temperature gauge while driving, as fan malfunctions can easily damage the engine and increase repair costs. It's best to have professionals test the cooling system during regular maintenance to avoid roadside breakdowns.
