Drive Belt Idler Pulley Replacement
What is a drive belt idler pulley?
The term “Drive Belt” is a generic term used to describe a set of belts that are used to run engine accessories such as the alternator or power steering pump. These belts must be routed in a manner that prevents contact with other belts or components, necessitating the use of an idler pulley. This helps locate the belt, while allowing it to spin freely.
How does the drive belt idler pulley work?
While the engine is running, the crankshaft pulley is constantly spinning. This provides drive to other mechanisms by means of a belt. The belt will be tightly wrapped around the crankshaft pulley and the accessory pulley, so the belt is unable to slip. Manufacturers use idler pulleys to route the belt around various engine accessories.
What are the symptoms related to a bad drive belt idler pulley?
If the drive belt idler pulley fails, there will be a very audible chirping noise from the front of the engine. This is because the idler pulley bearing is no longer smooth, and rotating causes metal to grind at high speeds. If it is not changed immediately, there is a chance it will become dislodged, or allow the drive belt to slip off. If the belt falls off, the accessory that it drives will no longer function. For instance, if the alternator belt idler pulley fails, the alternator may stop functioning. Also if the pulley begins to wobble, allowing slack in the belt, it will make an extremely loud squeaking or screeching noise, especially on cold starts. This is the belt slipping on the crankshaft pulley, and will require belt replacement once the idler pulley is replaced.