The fan clutch is a cooling system component that controls the operation of the engine cooling fans. While many newer vehicles now use electric cooling fans to keep the engine cool, many older vehicles used a mechanical fan clutch to control the fans. The fan clutch is a thermostatic device, which means it operates based off temperature, and is usually mounted on the water pump, or another belt driven pulley. The fan clutch will spin loosely until the temperature reaches a certain level, at which point the fan clutch will fully engage so that the fan can work at maximum efficiency. As the fan clutch is a cooling system component, any issues with it can cause overheating and other issues. Usually a bad or failing fan clutch will produce a few symptoms that can alert the driver of a potential issue.

1. Vehicle overheating

One of the first symptoms that is commonly associated with a bad or failing fan clutch is an overheating engine. The fan clutch is responsible for controlling the operation of the cooling fans. A bad fan clutch may not engage properly or at all, and as a result, will disable the fans or prevent them from working at maximum efficiency. This may result in the engine overheating, which will lead to more serious issues if left unattended.

2. Excessively loud cooling fans

Another common symptom of a faulty fan clutch is excessively loud cooling fans. If the fan clutch gets stuck in the engaged position, which is not uncommon, it will cause the fans to fully engage even when it is not desirable for them to be on. This may result in an excessively loud engine from the fan blowing at full speed. The sound may be easily audible and present at all times when the engine is cold and hot.

3. Decrease in power, acceleration, and fuel efficiency

A decrease in performance is another symptom of a bad or failing fan clutch. A faulty fan clutch that leaves the fan permanently engaged will not only cause a noisy engine, but can also cause a decrease in performance. A stuck fan clutch will cause excessive, unnecessary drag on the engine, which can cause a drop in power, acceleration, and fuel efficiency, sometimes to a quite noticeable degree.

As the fan clutch is one of the main cooling system components, it is very important to the proper operation of the engine. When it fails, the engine can be put at risk of serious damage due to overheating. If your vehicle is displaying any of the symptoms above, or you suspect that your fan clutch may be having an issue, have the vehicle inspected by a professional technician, such as one from YourMechanic, to determine if the car will need a fan clutch replacement.

This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Fan Clutch and was authored by Eduardo Ruelas.


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