What Causes Abnormal Noise from Car Engine Belts?
2 Answers
Engine belt abnormal noise may result from the following reasons: 1. Friction sound between the timing belt and timing cover: This usually occurs even when the engine is warm. If the noise is not loud, it can be ignored and won't affect the belt's lifespan. 2. Aging of the drive belt may cause a "squeaking" sound during vehicle startup: Since drive belts are primarily made of rubber, which hardens and becomes brittle in winter, the friction coefficient decreases. 3. Excessive belt wear can also produce a "squealing" sound: Aged rubber belts have reduced friction and cannot effectively transmit power, leading to slipping phenomena.
I've driven quite a few cars and encountered engine belt noise issues several times. The most common cause is belt looseness, which creates a squeaking sound while driving due to insufficient tension causing slippage. Another reason is belt aging or wear, especially after several years when the rubber cracks and deforms, producing a whistling-like noise. Also, pay attention to tensioner pulley problems, such as bearing damage, which creates louder noises. Once I heard a sudden rattling noise on the road, and later found it was caused by oil or dust contamination on the belt, worsening the slippage. If these issues aren't addressed promptly, a broken belt can cause major trouble, potentially leading to breakdowns or damage to other components. Regular inspections are crucial—I usually check my belt condition every six months, testing the elasticity by hand or using soapy water to assess tension. Don't skimp on replacing an aged belt to avoid being stranded midway.
