So im going to change my idler pulley tonight after work, but not real sure of the pulley itself. Am i OK to go with Dayco or should i grab the OEM pulley? huge price difference

 

So, for those watching i changed the pulley in about 10 minutes with a friend holding the belt (so we didnt need to take it off) and the whine remains. The belt looks new, the pulley looked fine (i got Dayco) and i dont show any symptoms of alternator issues. Tensioner pulley?

Gonna have the alternator checked just to be safe and if it checks out im trying a new tensioner pulley.

 

What type of belt are you running? I had a similar issue and through searching the forum I learned that these trucks like a Goodyear Gator back belt so I threw one on and never had another sounds since!

 

Yeah thats a good idea, im gonna pull the belt off and check it out. its in great shape but so annoying id rather get a new belt. the gatorbacks are highly recommended round' these parts

 

Success. After trying an idler pulley and a new tensioner i started to play around with my AC and sure enough it turned out to be the AC clutch. Got a new belt (705k6 fits perfectly) and bypassed the AC for now until i can go to the pick a part. No noise and some more acceleration too. Ah, the sound of silence:ico n_banana:

 

Thursday night, my Blazer dropped its serpentine belt, no P/S, muscled it home. Friday I discovered why: a dry bearing in the idler pulley had seized. Bought a new pulley and belt (both Duralast) $55. New pulley has a much-better sealed bearing than original.