What noise might indicate a worn serpentine belt?

A worn serpentine belt is most commonly associated with a squealing or squeaking sound when the engine is running. This noise is typically caused by the belt slipping on the pulleys due to wear, reduced tension, or contamination from oil or coolant. The serpentine belt plays a crucial role in driving several engine accessories, and if it is not making proper contact with the pulleys, it can produce these characteristic sounds.

Squealing is often more noticeable during engine startup or when the engine is under load, such as when accelerating or using power-steering assistance. Recognizing this noise helps technicians diagnose the issue before it leads to further complications, such as complete belt failure, which could affect a vehicle's operation significantly.