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Automatic Belt Tensioner

Q: I was told that a serpentine belt should last 100,000 miles or more. But on my car I had to replace the serpentine belt twice over the last year. What could be the problem?

A: Serpentine belts can last over 100,000 miles. You should not have to replace the serpentine belt twice in one year. The problem could be a worn automatic belt tensioner and/or idler pulley. The belt tensioner keeps the belt tight and vibrations to a minimum. If the bearing on the tensioner is worn, the belt may get out of alignment causing wear on the sides and fraying. If the spring on the tensioner is worn, the belt can slip and cause glazing of the belt’s surface. Glazing leads to belt squealing. When replacing the belt, check the belt routing diagram sticker (usually in the engine compartment) to make sure you correctly installed the belt.