Took the Vette out to run some errands last evening. As I was pulling into a parking space, an odd, rhythmic squeal started from the front of the engine compartment. Put it in park and it stopped. Shut it down and took a look. Did not see anything obvious. Restarted and no noise. On the drive home, I could hear a similar noise every time I ran over a small bump but only for a second. Got her back to the garage and could not reproduce the noise. This AM, it started fine. Let it warm up about 30 seconds (58 degrees in the garage), put it in reverse the squeal started again! Park – no noise. Opened the hood, put it in reverse and set the parking brake. As soon as I released the foot brake, the squeal stopped! WTF! Belt appears to be fine and not abraded anywhere. Nothing that I can see comes in contact with water pump, air pump, PS, alt, or crank hub. Funny that it would start so suddenly. I won’t be able to check any further until I get home Thursday.

Has anyone heard of this before and where do you suggest I start looking?


Bill


[Modified by Steel Blue 91, 6:35 AM 3/25/2004]

 

Well :confused: I would start by eliminating the obvious. Take off the serpentine belt and re-fire it up. If, it goes away you need to spin each pulley one at a time and one of them should talk to you :) . If noise stays. Try the buddy system. One guy makes the noise and the other one listens up front. Good luck and let us know what you find. :thumbs:

 

That's how I found the water pump last fall. Just can't think of what would flex enough to rub in reverse with the brake on. :confused: Gues I'll start from square one when I get home.

 

Hope its not a wheel barrin or p.s. pump. Could be something simple though.

 

:iagree:

That is what I would do to try and islotate the source of the sound.

 

I had something similar happening on my Impala SS LT-1. The noise occurred mainly while steering at low speed, like in a parking lot. Although, it did occasionally occur at low moving speed like backing up as well. Turned out to be the balancer. Since the balancer doubles as the pulley on LT-1s, the rubber between the outer ring (pulley) and the innner section that is bolted to the hub had shrunk and/or worn out and the outer ring was slipping around the inner section. Take off your serpentine and try to spin the outer ring by hand. If you can do that at all, that is your source.

Let us know what you find. I am curious about this one.

 

Monitor charging voltage on the dash.

If the squeal goes away when charging voltage rises check out the alt.

 

Update: Was able to play with it a little this morning before work. Removed the camber brace and belt. All bearings (Alt. PS, AIR, AC, idler) move freely with no noise. The hub/balancer could not be moved by hand and had no play. The squeal is still there when started without the belt, however, I'll need a second person to pin point the source. On a positive note, I did find the torx head bolt I dropped 2 months ago wedged in the exhaust manifold heat shield.

More later.

 

vaccuum leak?

 

Found the problem. Seems a previous owner had some work done that required the removal of this:



Well, when the "mechanic" - I use that term loosley - replaced the parts, this was left somewhere at the front of the engine. Taking a rather spirited corner the other night seems to have dislodged it from it's hiding place and wedged it between the balancer and the pan under it causing a hell of a noise. Notice the shiney part on the left of the bracket - that's were it was contacting the balancer.

Thanks for all the suggestions and help.

 

That doesn't look familiar. Where does it mount?

 

Yeah! What the hell is that thing?

-JRC-

 

In the "mechanics" posterior region, inserted with a good swift kick. :smash:

 

And no lube :lol: :lol:

Glad you found the source of your mysterious sound. :thumbs:


:party:


[Modified by 86PACER, 11:56 PM 3/25/2004]

 

I bet it's RPM related.

Idling in neutral, the noise may be higher pitched so you can't hear it as well. In gear, the RPM makes the noise lower-pitched and it becomes audible. Check the belt-tensioner bearing. Flood it with WD-40 and see if the noise changes at all. If it does, that's your problem. The bearing is only $9.20 at a bearing house and they can press it in for you. Since there's only two bolts involved (one bolt holding the tensioner on. One more that holds the pulley on the tensioner) you can take it off in the parking lot, have the bearing put in, reassemble and drive home. If it is the prob, please don't pay $100 for a new tensioner assembly plus installation. We are smarter here.

Hope this is helpful,

BIG JIM

 

I have seen similiar brackets around the a/c or accesories. I have to go look at my car but I know on my truck there is almost the exact bracket to help reinforce the back of the tension pulley to the intake manifold. I think I can remember a similiar bracket on my brother's 90 when I had to remove some of the a/c to change the water pump.