[JSchmitz]

Originally Posted by Scarebird

I was still getting plagued by belt squeal. The other day I was getting ready to drive away and started to hear a flip-flip-flip noise; opened the hood in time to see the belt come off and partially disintegrate. Mnnh.

I noted the tensioner pulley had a coating of rubber while the water pump was shiny. Idler faced the inside of the belt but did not have grooves. My guess is the grooves on the belt were squirming around the pulley, making noise. I replaced the tensioner pulley with a grooved unit. Will test when the bad weather passes. Used 38009 (76mm) pulley. 38008 is 70mm.

I also cleaned off the tensioner pulley and used it as an idler as it was wider than the existing idler pulley.

I had a squeal on my 5.3 when I started it up. It was a brand new belt. Don't recall what brand. Maybe O'reilly house brand. I had a larger diameter idler. Tried that first. No help. I swapped it for a Dayco belt and it stopped.