The alternator, power steering pump, water pump, and air-conditioning compressor are all driven by one serpentine belt. Due to their composition and the stresses they are subjected to, drive belts stretch and deteriorate as they get older, necessitating periodic inspections. The serpentine belt has no adjustment for tension, unlike older systems with multiple V-belts. The engine has a tensioner that automatically applies the right belt tension and compensates for belt stretch over time. With the engine off, open the hood and locate the drive belt. Using a flashlight, check the belt for various signs of wear and tear. Both sides of the belt should be inspected, which means you will have to twist the belt to check the underside. Use your fingers to feel the belt where you can't see it. If any of the above conditions are evident, replace the belt. Rotate the belt tensioner clockwise to release the tension, then slip the belt off the pulleys and slowly release the tensioner. Route the new belt over the pulleys, again rotating the tensioner to allow the belt to be installed, then release the belt tensioner. Ensure the belt is properly centered in the pulleys. To replace a tensioner that can't properly tension the belt or one that exhibits binding or a worn-out bearing/pulley, remove the drive belt then unscrew the mounting bolt and nut. Installation is the reverse of the removal procedure. Tighten the fasteners to the torque values. Install the drive belt.