The idler pulley is essential because it is in charge of routing the timing belt so that it remains in the correct position. There can be one or more pulleys along the timing chain and each can come in different sizes.
Idler pulley functionThe main function of the idler pulley is to provide tension and conduct the engine drive belt. The belt wraps around numerous components of the engine. It wraps around components like the power steering pump, alternator, and water pump, so the idler pulley makes sure the entire system runs efficiently.
Common problems with a faulty idler pulleyA faulty idler pulley can cause overheating, stalling, and a decline in tension.