Q: I changed a worn serpentine belt yesterday and today after only driving for 40 miles the new one is severely worn. What would cause this?
A: You may have installed it incorrectly. Look to make sure the belt ribs are in all of the pulley grooves. Check each component (i.e., power steering pump, water pump, crankshaft pulley, AC, etc.). A common mistake is to get the belt off a groove. If you know you installed it correctly then check the pulley alignment and belt tensioner. The sides of the belt can wear quickly if the pulleys are not aligned or if the belt tensioner is severely worn. You will need to find the source of the problem and replace the belt again.