If a customer comes in with a fan clutch that’s making unusual noises, there’s an issue that needs to be fixed as soon as possible. If you’re not sure what’s wrong with their fan clutch, let’s narrow down the issues by identifying the noise first.

Here’s a list of the most common fan clutch noises and what each one could mean:

1. Roaring

Engine bay noise

Sometimes a customer will complain about a roaring noise coming from the engine bay. It’s often compared to a jet engine.

A roaring noise could mean a number of things, including a bad wheel bearing, worn tires, or a differential that’s low on oil. Often times, it’s the fan clutch. When the clutch shoe inside the part gets stuck, it fails to disengage. This causes the fan to lock up on the input shaft. When the fan is locked up, the cooling fan is permanently engaged. This causes the roaring noise.

You can ask the customer a few follow up questions to determine whether the fan clutch is the culprit behind the roaring noise. Here are a few questions you can ask:

  • When do you hear the noise?
    • All the time? Or just some of the time?
    • When accelerating?
    • When coasting?
    • When cornering?
  • Is the engine running cooler than normal?
  • Is the heater making less heat?

Diagnosing this issue is pretty easy. All you have to do is to pop the hood (with the engine off) and then try to move the fan blade. If it won’t move, then it’s locked up and the customer needs to have the fan clutch replaced.

2. Clunking

Sometimes a customer will hear a clunking noise when the engine is running. It’s a common sound that could mean so many different things, including broken clutch fan blades. You can open the hood and then inspect the clutch fan (with the engine off, of course). If you find any broken blades, then the fan clutch needs to be replaced as soon as possible.

3. Whistling

A whistling or whining noise coming from the engine bay can be pretty serious. There’s a number of possible causes for the whistling noise, but one of the most common causes is a loose serpentine belt. When this happens, the fan clutch is not engaged properly. To help determine whether the serpentine belt may be loose, ask the customer a few questions:

  • Does the power steering feel a bit off?
  • Does the A/C feel weaker?
  • Is the engine running hotter than usual?

You can always check the serpentine belt and the tensioner pulley. If the belt is indeed loose, replacing it (and fixing the tensioner pulley if it’s broken) should put the fan clutch back in working order. (Of course, not all fan clutches are driven by the serpentine belt.)

Why You Should Convince the Customer to Replace Their Fan Clutch ASAP

Fan clutch

Image Credit: 4x4Xplor

If there’s an issue with the fan clutch, the customer needs to have it replaced right away. The longer the customer leaves a malfunctioning fan clutch in their engine, the more engine issues will crop up. The biggest risk is that the engine may overheat. They may also see a reduction in engine power and/or a decrease in gas mileage. If their engine overheats, they’re looking at hundreds or thousands of dollars in repairs. You know what they say: an ounce of prevention is worth a pound of cure. So it’s important to let the customer know how important it is to replace a bad fan clutch as soon as possible.


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