annoying squeal

[Ramairgod84]

ok so here it is. my 01 ws6 started to develop a squeak/squeal a while back. So I changed both a/c pulleys, and the serp tensioner pulley, and it's still there. The belts are fine, no cracks. I dont have any leaks either. The car's got 113,000 on it. What could it be?

also, I put strano springs, bilstein shocks on my car a while back, and when i go over small bumps on the road, it sounds like there's a squeaking sound coming from the rear passenger side. i dont know if it's an exhaust part squeaking or if it's something suspension. any ideas? When i back out of my drive way, i hear a small clunk sound coming from that side suspension as well

[Z28_Driver]

Take a look at the bolts in the rear suspension. Could be one backed out a little.
At least that was the problem on mine not too long ago.

[TransAmX2]

If the belts are routed the same as mine (98) you have 2 serp belts, the main and the AC. I'd take the AC belt off and start the car, see if it goes away (narrow down the search).

Then you have 2 Tensioners 1 for AC belt and 1 for Alt/PS belt , and at least 1 idler pully for each. My stragety is: Take a pully off one at a time, spray the back of it (the bearing part) with WD40 spin it a few times, clean it off, reassemble, see if noise changes, once it does change that's your bad bearing, get a new one
WD40 won't fix a bad bearing, but it will clean debris out of it and change the sound it makes when spinning.

Odly enough when I had one go it was cheeper for Advance Auto to sell me a new pully with the bearing in it than it was to buy a new bearing and press/swap it out.

Rear noise: I'd start with the exhaust, just grab the right exhaust tip (either when cold or with gloves on and wiggle it around, up/down, right left, see it it produces any noises. Suspension: carefully push down on your right rear quarter pannel and see if you can reproduce the squeak and narrow down the point of concern. Have a friend repeat process while you are under the car (with rear of car on ramps not jackstands) so the suspension actually moves.

Narrow down noises, if it's suspension, check for damaged components, disassemble clean it off, lube it up and reassemble. Exhaust: check for damaged parts or parts hitting, adjust what you can to fix it, bring it to a exhaust shop if necessary.