I have a 2002 Chrysler Voyager with 135000 miles and in good shape. My mechanic has replaced the serpentine belt 3 times in the last 24 months each time using a different manufacturer. The last time was <6 months ago. The tensioner pulley was replaced 10 months when the screeching noise returned as it has each time the belt is replaced. The other pulleys all seem to work fine. I use a small fingernail sized dab of NAPA’s “Sil-Glyde” lubricant on the underside of the belt every 150-200 miles. I will use it more frequently if it has rained recently.
-AC works fine and is not associated with this screeeching
-PS pump works fine and shows no leaks. Rack has been replaced. PS fluid system flushed and filled with new fluid.
-Alternator runs fine