Belt tension is very important, as a belt that is too tight will put too much stress on the bearings of the components it drives, causing them to wear out prematurely. A belt that is too loose will slip, causing (1) the belt to wear out quickly due to friction heat, and (2) inefficient alternator, air pump, cooling fan or air conditioner operation because much of the turning power supplied by the main drive pulley is lost.
The belts should be inspected and/or adjusted at 2,000 miles (3,221 km) and then every 4,000 miles (6,441 km). First, make sure that the belt is properly positioned in the pulley. Check the pulleys for damage. Inspect the belts for cracks and signs of fraying. These usually develop on the inner surface and extend into the backing or outer surface of the belt. Check also for glazing, a completely smooth appearance which indicates slippage. A belt that is in good shape will have a slightly grainy appearance like cloth. Replace belts that show cracks or glazing.
Check belt tension. Apply pressure with your thumb at the mid-point between two pulleys, and the belt should stretch or deflect about 1⁄4 – 1⁄2 in. (6–13mm). If the belt is too tight or too loose, adjust/replace as necessary.