New belt,alt,idler - fan squeal returns. HELP! 2000 GMC Safari

The drive belt on my Safari began squealing something fierce. I replaced the belt, and also the alternator and idler pulley as the bearings felt questionable on them. It ran perfect for about a week, until this morning when the squeal returned. What do I do now?!?

I had the same problem with my sons Jeep Wrangler, finally fixed it by switching brands of belt. Make sure all the surfaces are clean and get a new belt. Some folks say a Goodyear Gator belt is the way to go.

The Goodyear Gatorback Poly-V belt is the best choice for my 2000 Blazer 4.3. Other belts, especially the Dayco brand are noisy from the start.

Ed B.

With the engine idling, look carefully at the PATH of the belt around the pulleys. Look at the pulleys. Are they square to the plane of the belt? Are any pulleys tilted or side-wise? Only as few degrees off counts as tilted, or not running true.
If the run of the belt isn’t true, to a very small degree, the belt can squeal.
If any component isn’t running true (except warp), the component can be shimmed to true with washers or spacers.

You can’t go wrong with the Goodyear Gatorback.

I checked the path of the belt, and noticed what could be described as a warped crankshaft pulley hub - not what I wanted to see. Would changing the hub be possible without removing the crank (which in this case, would require the body to be removed)? Oddly enough, spraying the belt with belt dressing made the noise far worse, and spraying it with Armor-all quiets it for a day or so. Would a Goodyear Gator back belt quiet the noise without solving the misalignment problem?

Thanks for all the help guys!