That year model has the tensioner with an allen (inhex) screw on front that needs to be removed and the plastic disc and the metal surfaces that contact disc need to be cleaned. To do this you must remove belt or at least take it off one pulley so that tensioner will be at rst so you can remove it from bracket. Now take out the allen screw and clean up the tensioner. You need to apply a silicone grease to the metal surfaces that will contact plastic disc. You could also buy the new style which doesn't need to have periodic maintenance and use it instead.

If the tensioner gets bound up internally it won't keep constant pressure on belt and it will chirp as it slips and grabs mostly at idle speeds.