I hope there will be some good answers to become of this.

1999 Chevy Lumina 3.1L/3100 (L82) (Base Model)

I have had a very annoying and sometimes very loud squealing coming from under the hood. Mostly when the car is under acceleration, and sometimes even at idle. At first I grabbed a can of silicone lube and sprayed where I thought the sound was coming from, which was my power steering pump pulley. Though I had no trouble with the power steering, I thought that the bearing in it was going bad. That did make the squealing stop, but only for a very short time. Usually about 1 to 5 miles. I only did this until I could come up with enough money to buy a new pump, as I thought this was the issue. After replacing it, I noticed that the squeal was still there, though not quite as bad, but still very annoying. So I got to listening again, and sprayed my idler pulley thinking that bearing was going bad. The squealing stopped again, and again only for a short while. So I just replaced that today, with a brand new pulley (I'm beginning to wonder if they all were squealing). However the squealing is still there, though not as bad, but not much better either. It still wants to squeal under acceleration. So me and a friend of mine got to looking again, and trying to troubleshoot the culprit. There was only a couple more things it could be. I was hoping it wasn't the crankshaft bearings, but there is no rough idle or anything, so I put that idea to the side for the moment. I reached up and tapped (turned) the accelerator cable bracket on the throttle body to rev up the motor to make it squeal so we could see where it was coming from. It appears it was coming from the AC clutch the whole time (or maybe all 3 were squealing). I've looked everywhere on the net about what may cause this, and the answers vary greatly. I think it may be the AC Clutch bearing, but I have read that it may be the clutch itself, or it may be the air gap in the clutch needs to be readjusted (A side note: Because I did spray it with silicone lube, and it's location at the bottom of the motor, I can't tell if there is or was any metal shavings or dust for those of you who may ask me to look). I read a few places that it's best to buy the clutch replacement kit which comes with the bearing (quite expensive too, vs. just buying the bearing), and I hope like hell I don't have to pull the motor to do it, if I don't have to, but I know that I might need to in order to pull off the clutch pulley, to replace the bearing if that's what it is. I think I can work on it from the bottom of the car. Only thing that looked like it was in the way was a plastic cover. Probably part of the air dam. Another option I also considered was just getting a belt to bypass the AC compressor all together, however I didn't see that option when I was looking online at the parts stores for prices on all of this. I believe that the AC's came stock on all the Lumina's, even a base-like model, like mine is. I don't know the exact length the belt would be if I did bypass it for now. That option worries me a little because I'm not 100% certain that the defroster is directly related to the AC or my heater core. Seeing how it's usually snowing here, I definitely have to have heat going to the windshield from time to time, especially in heavy snow. I think mine is linked to the heater core because it stays hot even when the car is idle (not to mention like I said before, I never saw the clutch engage when it was idle with the defroster on, and it only gets hot when the motor is warmed up), unlike (and I could be mistaken) if it's linked to the AC, it would be cold at idle (even with the motor warm), until the RPM's of the engine picked up and then the air would get hot when the compressor kicks in above a certain RPM range. (Some vehicle computers will increase the idle just enough to run the AC with the clutch engaged, while still at idle, though this is more of a common occurrence for the air conditioning than the defroster.) (I've actually seen this in the previous car I owned before it was totaled and I had to get this Lumina.) If my defrost is linked with my heater core then I could just bypass the compressor for now, until I can afford to buy a whole new compressor with clutch (though the one I have now works great, other than the squealing noise). Anyways, enough of me rambling on. What do you think may be the problem here, or any suggestions to further narrow down the problem, so I can get this squealing fixed without spending a couple hundred dollars.

 

I ended up measuring out and buying a shorter belt to temporarily bypass the compressor, so I didn't have to drive around embarrassed at the extremely loud squealing. I still need an answer however or suggestions, as to what the problem may be.