x2 on checking ALL the pulleys... make sure they turn smoothly with no wobble or grinding noises.... replacing the pulley and belt is very easy.... just be careful with the tensioner so you don't pinch something that hurts.....

Also check the heater hoses on the passenger side by the alternator for any damage..... I was checking the alternator pulley bolt size Saturday and found that my heater hose has wear damage from when I lost my Tensioner pulley on the highway a couple of months ago.... no leaking or issues, but glad I saw it now and will find a new one today and get it on its way....