Idle Pulley Noise – Causes in A Truck

Have you ever experienced idle pulley noise in your truck? The idle pulley has various bearings that wear out with time. This guide explains some of the reasons for a noisy idle pulley. Unusual noises from your truck can be very uncomfortable, and you need to investigate them as soon as you hear them. When your truck starts to produce the idle pulley noise, always never ignore it because it usually escalates into significant issues.

The pulleys perform the role of holding various belts in their respective positions. If one fails, other parts of your truck engine could be affected.

The idle pulley and belt are located at the front part of your engine. The belts usually rotate as your engine is rotating. To locate the idle pulley, you must look at the serpentine belt that moves on the engine.

Most trucks have only one idle pulley, but some have more depending on their configuration. Rail-type mounts give the idle pulley adequate tension, which puts it in its place. Some idle pulleys use spring tension.

Causes of Idle Pulley Noise

Worn out pulley or slipping serpentine belts are some f the common causes of idle pulley noise. If the pulleys are damaged, they will make a loud noise. Here are some causes of the idle pulley noise in your truck.

Damaged Pulley

It will completely break when your pulley shows signs of being faulty and you ignore it. When the wearing is constant, the pulley will develop cracks with time. The first time it will break a little bit, creating a chain reaction you never want to encounter. When your pulley is damaged, the serpentine belt will tear.

If your serpentine belt breaks, prepare to deal with more significant problems. Your engine will overheat or stall. You are also likely to hear a consistent squealing noise which will give you an annoying ride.

Slipping Belt

When your pulley is worn-out, it will give you signs. If you ignore this sign, the problem will escalate, and your belts will start to slip. A slipping belt happens when the pulleys are entirely worn out.

The pulley will bind and rub along the engine belt, producing squealing noises. The binding between the pulley and the engine belt will produce a squealing noise as your truck is in motion, which will get worse if you do not replace the pulley. The slipping belt can also damage other engine components, which will make you spend a lot during repairs.

Worn Out Pulley

The idler pulley usually spins with the drive belt as you drive your truck. The repeated use leads to wear and tear of the pulley. Your pulley will start to develop marks and scuff as it becomes old. The premature wear will cause minor noise but worsens gradually the more you ignore it. 


When the idle pulley becomes faulty, your truck will produce unnecessary noise. This guide has covered the three common causes of idle pulley noise. Knowing such causes will enable you to make adequate preparations to repair the problems related t idle pulley noise.