Belt Squeal Mystery - Need Help

Hey Everyone,

I have a 95GT with bolt-on's that I've been having accessory belt issues with for the past two seasons. Last summer the car was making a ticking noise which turned out to be a bad belt tensioner. I replaced it this winter with an aftermarket unit from Summit Racing.

This spring my first trip with the car it threw the belt off which I thought was really odd. It destroyed the belt in the process, so I purchased a new Goodyear Gatorback belt. I also noticed that the belt was riding on the front of the new tensioner pulley which I thought was maybe why the belt came off.

So I used a 1/4 spacer behind the tension to push it out so the belt rode on the middle of the pulley. The belt no longer flew off but now I had horrible belt squeal at startup and a slight chirping at idle. I figured maybe my spacer meant that the tension was not 100% straight and thus causing the squeal, so I went back to no spacer and the squeal is still here.

So three things come to mind now. One; my new belt could be glazed from the squealing and needs to be replaced again. Two; the aftermarket tensioner is crap and I should replace it with a Ford unit, or Three; I noticed a lot of rubber build-up around the alternator and perhaps my alternator is the cause? It is charging find and spins freely, but there is a lot of build up around it. Pictures attached to maybe help.

Thoughts?

Thanks for your response, I appreciate it. I had zero squealing issues last year before I replaced the tensioner. Ever since I installed it I have belt squeal and a thrown belt. My first instinct is to throw the $70 I just spent away and buy a $110 Ford tensioner (or an aftermarket piece that someone can recommend). Here is the Ford one on CJ Pony Parts: Ford Mustang Belt Tensioner W/ Pulley 5.0L 1994-1995

I am running a 90.2" belt. I have all stock accessories (including A/C) but no smog pump. I have spun all the accessories and they seem good. The only one that maybe suspect is the idler. It spins but maybe only two rotations by hand before it stops again. I'm wondering if it should spin more free than that?

Any other suggestions let me know.

Thanks again for the responses. I have removed the spacer from the tensioner but the squeal continues. I am now getting a constant chirp as well that increases with the speed of the engine. I may try a new smaller belt to see if that helps. The aftermarket tensioner does not have a mark to indicate if it is in the right range, but I do see it on the original OE piece I still have.

I found my issue. I replaced the belt with one an inch shorter and my squeal is gone. I guess different branded belts do have a significant difference in length.