What Causes a Fan Clutch to Fail?
3 Answers
Fan clutch failure can be attributed to the following causes: damaged bimetal temperature sensor, silicone oil leakage, or broken silicone fan drive pin. Details are as follows: Damaged Bimetal Temperature Sensor: When the bimetal temperature sensing port is damaged, the fan clutch cannot engage or disengage in response to the air temperature behind the radiator, remaining permanently disengaged. This results in engine overheating. Silicone Oil Leakage: Silicone oil serves as the primary transmission medium in the fan clutch. When leakage reaches a certain level, power transmission fails. Broken Silicone Fan Drive Pin: This causes the oil outlet valve plate to remain open under spring force, allowing silicone oil from the reservoir to continuously enter the working chamber. Consequently, the fan clutch remains engaged, leading to excessively slow engine warm-up.
I've been driving for almost ten years and have encountered fan clutch failures several times. The causes are usually mechanical wear, like the small bearings wearing out over time, lubrication drying up, or external debris getting stuck inside. There are also electrical failures, such as loose wiring connections or short circuits burning out internal circuits, especially prone to overheating and failure during high summer temperatures. My neighbor's car once had its fan clutch burned out because they forgot to replace the coolant, causing the engine temperature to skyrocket. For prevention, regularly check the cooling system, change the lubricant in time, and avoid prolonged high-speed operation that overheats components. If it fails, get it fixed immediately—otherwise, uncontrolled engine temperature can lead to serious issues. It's best to replace the part at a reputable repair shop without delay. Safety first.
I worked in an auto repair shop for several years. Fan clutch failures are commonly caused by wear and tear or electrical issues. Bearings and connecting components often age quickly due to lack of lubrication, and corrosion or short circuits in electrical interfaces can also be contributing factors. I recall one case where a vehicle's fan speed control module malfunctioned, leading to overload and burnout, compounded by the owner's long-distance driving without proper maintenance accelerating the damage. During inspection, start by checking for visible cracks or leaks, use tools to test if the resistance is normal. For simple issues, try replacing a fuse, but for deeper problems, it's best to consult a professional technician with diagnostic equipment for scanning. Regularly replacing coolant and cleaning the radiator can significantly reduce failure rates.
