What Causes the Noise from the Corolla's Belt Tensioner Pulley?
2 Answers
Tensioner pulley noise is caused by improper adjustment of the tensioner or aging of the belt. How to determine if it's the tensioner pulley making noise: To determine if the noise is from the tensioner pulley, you can only use the elimination method. Either remove the belt to check if the tensioner pulley is noisy, or replace it with a new belt and listen for any remaining noise. Possible other sources of noise: In winter, belt noise in vehicles is mainly due to the cold weather, which hardens the rubber and reduces its elasticity, causing slippage between the tensioner pulley surface and the rubber surface. Therefore, it's not about the belt being too loose or tight, but rather the rubber becoming too hard, reducing friction and causing slippage, which results in noise.
I've repaired quite a few Corollas before and encountered this kind of tensioner pulley noise issue. The most common cause is worn tensioner pulley bearings, which could be due to prolonged use or a dirty environment. When the bearings rotate, they make an annoying 'squeaking' sound. A loose or cracked belt can also cause the tensioner pulley to malfunction and create noise. Another possible reason is rusted brackets or loose mounting bolts, causing the pulley to wobble. To diagnose, start the engine and listen for the source of the noise. If you hear a 'grinding' or 'clicking' sound, it's most likely a bearing issue. Replace the tensioner pulley assembly promptly, otherwise a broken belt could affect the alternator or air conditioning system, leading to more expensive repairs. Regularly cleaning engine bay dust and checking belt tension can help prevent this problem. For specific operations, it's best to have a professional mechanic handle it at a specialized shop.
