I have a Roush 427 in my Superformance. When the car was new, I had to trade out the serpentine wide belt for a grooved belt because I added a vacuum pump. Ever since (9000 miles now) when I turn on the lights or the fans come on the alternator has squealed at low RPM right after starting.
Today for no apparent reason it started screeching from start up and through a 20 mile drive and would not stop except at idle. At idle it showed pulling a few Amps but as soon as I accelerated the amps dropped to zero and the screeching started.
The belt is tight and I have kept it tight but no matter how tight I get it, it will still make noise at start up with the lights or the fans on before today.
The pulley has some grooves in it on one side, and it appears that the belt is primarily running on the edges and it looks like the edges actually made the grooves in the pulley. The belt sides (other than the edges) look like they don’t even contact.
It’s not about tension….and the alternator was tested and it did not squeal under load at the shop on the bench. Also, the belt is only about 200 miles old. The water pump has 9000 miles on it and it turns free and not leaking. And, you can hear that the squealing is coming from the alternator anyway.
My quandary is more about the pulley size. It’s a 2 3/8” O.D. Does that sound like a normal size. It was put on when the pulleys were traded out for the “v” belt pulleys. How can you tell if it's a standard pulley?
Alternator squeal
Threaded Mode
