How do you change a serpentine belt on your truck?

Most likely you need to look for a grooved pulley that looks like it may not be related to any parts of the engine,(i.e. the water pump pulley, a/c pulley) this is the tensioner pulley. The tensioner pulley on my '97 GMC 5.7L is located just beneath the alternator. Inorder to relieve the pressure from the "tension arm" find a square opening molded into the pulley arm, and insert a breaker bar to use as a lever for relieving the tension. Some vehicles may need a ratchet and socket in order to move the tensioner arm. With a little effort to relieve the pressure, you can now remove the serpentine belt. Most vehicles will have a diagram in the engine compartment showing the specific route for the belt to go on the pulleys. I've found that the easiest way to install the new belt, is put the belt around all of the pulleys first then lastly on the tensioner pulley.