Posted on 1/30/2026
A squeak or chirp from under the hood has a way of grabbing your attention fast. It might only happen for a few seconds after startup, or it might show up when you turn on the AC. Either way, once you hear it, you start listening for it on every drive. Serpentine belt noise usually is not random. It tends to follow a predictable aging process, and it often involves more than just the belt itself. The belt, pulleys, and tensioner all work together, so when one starts wearing, the whole system can get louder. What The Serpentine Belt System Does Every Time You Drive The serpentine belt is a single belt that drives multiple accessories, such as the alternator, power steering pump on some vehicles, and the AC compressor. It loops around several pulleys, and the tensioner keeps the belt at the correct tightness so it grips without slipping. Because the belt is constantly moving and bending, it wears with time and heat cycles. The pulleys and tensioner also wear because ... read more