What Causes Car Belt Noise?
4 Answers
It may be caused by a reduction in the friction coefficient of the belt surface or excessive wear of the belt, requiring timely inspection and replacement. If the noise occurs when the vehicle is under load, observe one of the drive belts. Generally, there is a belt wear length indicator at the bottom of the belt automatic tensioner. If the pointer exceeds the range, it indicates that the belt is excessively worn and needs to be replaced promptly to avoid more faults while driving. Methods to address belt noise: 1. If a noticeable noise is heard from the engine while driving, it may be due to a loose belt or excessive wear. Therefore, it is necessary to first check the engine belt. It is best to seek professional help to avoid causing other faults by attempting to fix it yourself. Checking the car belt while the engine is running carries certain risks and is not recommended. 2. You can identify which belt is problematic by listening to the noise. If the belt noise occurs when using the air conditioning, it may be due to an issue with the air conditioning compressor belt. If the noise occurs during a cold start, it may be due to a problem with the engine belt. This method can also help roughly determine the belt abnormality.
I remember when I was driving, the belt kept squeaking, which really annoyed me. There are several main reasons for this: the most common one is aging and wear of the belt. Over time, the rubber can harden or crack, increasing friction and causing slippage. Another issue is incorrect tension—if it's too loose, the belt flaps and makes noise; if it's too tight, it causes excessive wear on components, leading to squealing. Foreign objects entering the belt area, such as oil stains or dust buildup, can also cause slippage and strange noises. If the bearings in the pulley are damaged or misaligned, the belt won't function properly and will produce odd sounds. If not addressed promptly, the belt might snap, causing the car to stall suddenly and posing a safety hazard. That's why I regularly check the belt's condition, use a tension gauge to measure its tightness, and replace it if necessary. Driving safety is the top priority, so if you notice any issues, take your car to a repair shop right away.
During the process of repairing cars, I have encountered many cases of belt noise. The main causes are usually belt-related issues, such as excessive wear or surface hardening, which increases friction resistance and produces sharp sounds. Improper belt tension is also critical—too loose and it will wobble and make noise, too tight and it accelerates component damage. If the bearings of the pulley are damaged or the pulley is deformed or misaligned, the belt cannot transmit power properly, resulting in abnormal noise. If the belt is contaminated with oil or grease, it may slip and produce a dull noise. I recommend regularly inspecting the belt visually for cracks, testing whether the tension is within the recommended range, and cleaning the pulleys if necessary. If belt noise is left unrepaired, it can easily lead to belt breakage, affecting the engine cooling system or other components. It is advisable to seek professional inspection promptly to ensure vehicle safety.
I've driven many cars in my life and heard plenty of belt squeals. Usually the reasons are simple: worn-out belts due to aging, where hardened rubber causes slipping and squeaking; loose belts that tend to squeal during turns or acceleration; or pulleys that are rusty or greasy, making belt rotation less smooth. It's more noticeable in cold weather as rubber becomes stiffer and noisier. Whenever I hear the sound, I stop to check the belt tension—tighten it if loose or replace it entirely. Also, keep the pulleys clean to prevent dirt buildup. Don't procrastinate; a snapped belt mid-drive is a real hassle. Make it a habit to check monthly to avoid trouble.
