What Are the Causes of Engine Belt Noise?

[VivienneMarie]

Engine belt noise can be caused by: 1. The contact surface between the belt and pulley being too smooth; 2. Loose or aged drive belt; 3. Excessive load on the driven accessories; 4. Insufficient oil supply, preventing timely lubrication of the timing chain; 5. Excessive wear leading to a low friction coefficient on the belt surface; 6. Contaminants on the pulley surface; 7. Incorrect reverse installation of a used belt. Solutions for engine belt noise include: 1. Replacing the engine belt; 2. Replacing the belt bearing; 3. Applying a polyol solution to the belt surface; 4. Checking if the belt is installed in the correct direction.

[IkerFitz]

I've driven many cars, and engine belt noise is usually caused by several common issues. The belt may be too loose, insufficient tension can cause it to slip, producing squeaking or rattling sounds, especially noticeable during cold starts. Belt wear and aging is another factor—after years of use, the surface hardens and develops cracks, causing noise due to rough operation. It could also be a faulty tensioner or idler pulley, where the bearings aren't smooth, increasing friction. Oil or dust contamination on the pulley can also cause noise. I often inspect it myself by using a stethoscope or feeling the belt tension by hand; if it's loose, tightening it may solve the problem, otherwise, replacing the belt or repairing the tensioner is necessary. Don’t delay too long—if the belt snaps, it can be troublesome and affect the engine's normal operation.

[AryaDella]

When I first bought the car, I encountered strange noises from the engine. After checking, I found out it was a belt issue. In most cases, it's because the belt is loose and not tightened properly, squeaking more noticeably in cold weather or when starting the engine. Over time, severe wear and tear on the belt can cause surface cracks and deformation, leading to louder friction noises during rotation. If the tensioner pulley is aged or damaged, it can also make the belt operate unevenly. Additionally, heavy loads from auxiliary equipment like the alternator or air conditioner can cause uneven stress on the belt, resulting in noise. I remember once replacing the belt with a new one solved the problem. It's important to develop a habit of regularly checking the belt's condition, such as inspecting for cracks and tension every six months or every 10,000 kilometers, to prevent minor issues from turning into major repairs. Nowadays, whenever I hear unusual noises while driving, I take the car straight to a professional repair shop for peace of mind.

[CameronAnn]

The causes of belt noise are quite straightforward. Insufficient belt tension is the primary reason; a loose belt can slip, leading to noise. Belt wear and aging are also common issues, with noticeable friction sounds when the surface hardens or develops cracks. A faulty tensioner pulley bearing, which doesn't rotate smoothly, can also cause significant noise. Additionally, heavy loads on auxiliary components, such as when the air conditioning starts, increase the belt's burden. Accumulated dust and grease on the pulley can also cause problems. Addressing these issues isn't difficult. I usually start by measuring and adjusting the tension; if that doesn't work, I check the tensioner pulley or replace the belt.