Has anyone else encountered this? At idle my serpentine belt flaps almost 1 inch And makes a very audible buzzing sound. It isn’t slipping, and the air conditioning works fine and so does the alternator. Do I just need to replace the belt or should I replace the belt and the tensioner? I’ve never seen a serpentine belt do this.

 

Never mind. It’s a manual adjusting tensioner, not a spring loaded. No if I could just get that ball to move that adjust the tension…

 

*bolt

 

You need to loosen the nut at the center of the tensioning pulley first, then tighten the adjusting bolt. There should be 2 adjusters, one for alt/P/steering and another for A/C.
Make sure the pulley bearing has not gone bad causing such belt play(looseness), and there should only be 1/2" deflection of belt measured between P/s and Alternator pulleys. Do NOT overtighten the belt...it will cause bearing damage to the alternator and/or P/Steering pump.