Remove the serpentine belt and unbolt the tensioner.The tensioner slides off and is easily replaced.
REMOVAL & INSTALLATION-SERPENTINE (SINGLE) BELT
See Figure 21
Fig. 21: Pry back the serpentine belt tensioner and remove the belt from the pulleys
The serpentine belt drives the water pump, alternator, and (on some models) the air conditioner compressor.
Loosen the bracket lock bolt, retract the belt tensioner with a pry bar and slide the old belt off of the pulleys.
The spring powered tensioner automatically adjusts the belt to the proper tension.
Install the belt and release the tensioner. Tighten the lockbolt