A squeaky drive belt on your Jeep Grand Cherokee is a common problem that most owners will have to deal with sooner or later. The squeaking sound is caused because the drive belt is loose, which makes the engine pulleys turn uneven. When the pulleys turn uneven, they rub on the engine block which is made of metal and that causes the squeak. Before you adjust the drive belt, you should make sure that it is the drive belt causing the squeaking.
Start the engine and allow the engine to warm up about five minutes. Spray brake cleaner onto the drive belt and listen for the squeaking to stop. If the squeaking stops after the brake cleaner has been applied, then you know it is the drive belt.
Turn the engine off and allow it to cool. Allow the brake cleaner to evaporate before proceeding.
Pull the tension pulley towards the front of the engine using the pliers. Pull the drive belt off the tension roller.
Insert the Allen wrench into the hole on the side of the tension pulley. Turn the wrench to the right to tighten the spring inside the tension pulley. Replace the drive belt to the tension pulley the opposite way that you removed it.
Start the engine and listen for the squeaking. Repeat the previous step if necessary.
