1999 FRC - I posted before about a belt squeel noise that I couldn't figure out. I would get this noise that sounded like either a belt slipping or bearing noise coming from a tensioner or idler pulley. What made it more difficult to pinpoint was the fact that it would only do it while driving, and typically under light to moderate acceleration and also deceleration, it wouldn't make the noise just by free revving. After seeing so many posts about failed tensioners and noisy belts I assumed I would end up having to replace one or both tensioners as well as the idlers and belts. I did replace the belts with Gatorbacks, which made no difference in the noise. I then ran the engine with the AC belt off, still made the noise. I really didn't want to drive the car down the road with the main belt off. Then I got lucky and yesterday it made the noise by free revving the engine, then I could hang out the door and listen better, it seemed to be coming from under the car, it sounded exhaust related. I had read a post about the brace that is welded between the cats being cracked and making odd noises - sure enough, mine was cracked on one side. This brace is only about 1/2 wide and probably 1.5 long. I can't believe that is what was making the noise because it sounded exactly like a belt related noise. I bent the brace up so the broken ends weren't rubbing against each other and the noise is gone. Just wanted to pass this on in case anyone else was having the same problem.

 

thanks for that post - this is what I love about the forum .. anything happens to my vette and I have already read about it and know what to expect and do
next.