What Causes Loud Belt Noise in Cars?
2 Answers
The causes and solutions for loud belt noise in cars are as follows: 1. Pulley Contact Surface: The noise is often caused by excessive smoothness of the contact surface between the belt and pulley. This usually occurs when the engine speed changes rapidly, and sometimes increased load on belt-driven accessories can also cause belt damage. Solution: On vehicles without an automatic belt tensioner, measure the belt elongation using a standard belt elongation gauge at the midpoint between the two pulleys. If it differs from the standard value, it’s best to replace the belt. 2. Accessory Issues: Dirt such as sand on the pulley surface or incorrect belt installation (reverse direction) can cause prolonged squealing or sharp noises, often due to improper accessory assembly. Solution: Try reversing the belt installation direction to see if the issue resolves. 3. Bearing Lubrication: Continuous hissing or rattling noises that increase with engine RPM usually indicate insufficient lubrication in the accessory drive bearings. Solution: Replace the bearings or corresponding components. Important Note: Whenever replacing accessory drive parts, always remember to replace the belt tensioner pulley and automatic tensioner as well.
Recently, I noticed a loud noise from the belt while driving, which made me quite concerned. After inspecting it myself and consulting friends, I learned about several common causes. First, the belt might be loose, causing insufficient tension and resulting in slippage noise. Second, the belt could be aged or worn, with cracks increasing friction. Third, there might be issues with the pulley or tensioner, such as rust or dirt affecting rotation. I remember the belt made a particularly loud noise on a rainy day last time, and the mechanic said damp conditions make slippage more likely—applying some lubricant helped. It’s advisable to regularly listen for changes in noise and inspect the belt’s condition. If the noise persists, visit a professional shop promptly, as a broken belt could leave the car stranded on the road, compromising travel safety. Personally, I now check the belt tension and wear every six months to prevent issues.
