
Here are the causes of engine belt noise: 1. Mostly caused by aging of various belt groups in the engine: or issues with the tensioner pulley leading to overly loose belts, resulting in friction noise, belt slippage, etc. 2. Major belt groups and tensioner pulleys inside the engine: such as the engine timing belt, alternator belt, water circulation pump belt, air conditioning belt, power steering pump belt, etc. 3. Caused by excessive smoothness of the contact surface between the belt and pulley. 4. When the engine speed changes rapidly. Here are the methods to solve engine belt noise issues: 1. Check whether the accessories driven by the belt have bearing damage, seizure, excessive play, or increased power consumption. 2. Replace the belt, or lightly sand the contact surface between the pulley and belt with 100-grit sandpaper (gentle sanding is sufficient).


