Common Causes of Idler Pulley Noise and Cost to Replace

There are many drive belts within the engine which are linked to various components and accessories of the vehicle. Some of the most important components are the alternator, AC compressor, and power steering pump. When the engine is running, the drive belts start moving and these other components start activating. However, the drive belts must be guided by an idler pulley to do their job properly. That way, there is no interference between the drive belts and the other nearby components. Most importantly, the engine belt stays functional and rotates without any problems.

The average car engine only has a single idler pulley. You may find two idler pulleys in a specialized vehicle, but it is rare. For most of us, we must contend with a single idler pulley. This means that if the idler pulley goes bad at some point, you will experience some annoying and inconvenient symptoms. The most common symptom is squealing sounds arising from the engine area. If you fail to replace the idler pulley after a certain amount of time, the symptoms will escalate into something much worse for the engine.

3 Common Causes

Idler pulley noise is usually the result of up to 3 different causes. When you go to investigate the noise and verify that it is coming from the idler pulley, you’ll already be able to tell what the cause was. Below are the 3 possible causes which are explained further.

1) Damage to the Pulley

In rare circumstances, your idler pulley may suffer damage because of an accident, even if it’s a minor one. A damaged idler pulley often has lots of cracks form until it breaks apart entirely. You’ll hear noises throughout this process, so it won’t just happen out of the blue. But if you wait too long for the idler pulley to break apart, then it’ll cause the other corresponding components to break too, such as the drive belt.

2) Pulley Slippage

If the idler pulley were to slip and make contact with the engine belt, it’ll cause a plethora of unpleasant squealing sounds to erupt from the engine. You need to replace the idler pulley immediately or else the squealing sounds won’t go away. To make matters worse, the other corresponding drive belts will be affected by this too.

3) Pulley Wear and Tear

Like most components in a vehicle, an idler pulley does not last forever. When you think about how the idler pulley always spins whenever the engine is on, it incurs a lot of wear and tear each day. After driving for years with this kind of wear and tear taking place, it’ll cause the idler pulley to experience marks and scuffs on the outside. As the scuffs get worse, you will start to hear those strange noises. If you don’t replace the pulley, the wear and tear will only get worse and so will the noises.

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The Average Cost to Replace

Are you noticing a problem with your idler pulley? If you’ve heard strange noises coming from your idler pulley and have verified that your pulley is bad, then you’ll want to replace this pulley immediately. The average replacement cost of an idler pulley is anywhere from $90 to $195. The cost for another idler pulley part is about $45 to $95. If you go to a mechanic, their labor costs will probably be about $45 to $100. They’ll also add on fees and taxes to the total price as well. Still, this is not a terribly expensive replacement to get done. It is best for your engine if you go ahead and get this replacement when it is needed.

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