Niagara Gazette — •••
ALAN FROM NEW JERSEY: Why do my car’s belts squeal all the time? I own a 2006 Ford Focus with a 2.3 liter 4 cylinder engine. I have replaced the belts three times in the last three months and they still squeal, especially when the A/C is on. I am tired of replacing belts, so what else could be wrong?
TOM: Your car has only one drive belt called a serpentine belt. Check for a worn, glazed, or torn belt or a worn automatic belt tensioner.
Note that Alan keeps referring to “belts.” His car only has one belt that drives all the components, the serpentine belt.
Why is it called a serpentine belt? This type of system utilizes one long belt to snake its way throughout the pulley system driving all the components, hence its name Serpentine (snake).
How do you adjust the belt tension? Carmakers came up with a brilliant solution to this problem. They realized that if they stretched the belt out to the required length needed to drive all the components, then they would have to come up with a way to automatically adjust the belt as it stretched out with wear. The solution? An automatic belt tensioner. This device is a spring loaded idler pulley that rides against the back of the belt and keeps it adjusted to perfect tension at all times. As in the case of Alan’s car, these tensioners wear out over time and must be replaced. How do you know that the tensioner is worn out? The belt with squeal incessantly, especially when a load (such as the air conditioner) is added to the system.
How do I know when to replace the belt? A simple visual inspection of the belt will show signs of age, which include glazing, torn ribs, excessive wear, cracking, or fraying. Average serpentine belt life? 35 – 50 thousand miles.