Terrible Noise

I recently changed my alternator on my 94 lesabre, after doing so this strange terrible noise suddenly appeared. My brother (who knows more about cars than I) said it sounded like the air conditioner was making the noise, but my a/c is working fine. The noise starts when I start the car and continues till I turn it off, though it fluctuates in loudness. Can someone tell me what this could be and what I can do to fix it?
Thanx,
p_grasshopper

The alternator may be loose, causing a vibration, and hence a noise, but that depends on the noise you are hearing. Describe the noise as best you can, that way we can help without having to think as much (I have midterms this week and would like to keep my extra thinking at a minimal level). When the air is off, does the noise persist? What conditions cause the noise fluctuations?

let your wife out of the trunk

It's hard to explain the noise..kind of like a loud winding sound that comes from the front passenger side of the car. It doesn't affect the way the car runs, but the sound is loud enough to hear over the radio. The noise is there when the a/c is off or on, and fluctuates depending on speed, but only sometimes.

You said that you changed your alternator, the one you put on, was it new, rebuild or used. It sounds like one of the bearings in the alternator is bad. Ask your brother if he has a mechanics stethoscope to pin point the noise.

I'd bet it's the replacement alternator as well. Either the wrong model, improperly mounted, or you replaced it with a used one that had bad bearings to begin with.

Take that belt off and grab the alternator pulley. If you pull on it, is there a lot of back and forth play? Spin it with your hand and listen, does it make a noise? Turn it slowly and feel for resistance as it turns. -- Such things would point to bad bearings. For it to be making this much noise, the signs should be quite noticable.

Is the belt installed the proper way arond all the pulleys

Why did you replace the alt to begin with? Was it because the noise was present before the replacement? If you had a noise before you replaced the alt, I'll bet your water pump is bad. I've seen guys mistakingly replace the alt when the water pump was noisey. Very common.

water pump would be my guess, my moms car was making an AWFUL noise, and a week later, the water pump blew off the engine. (that was fun to fix, belt chunks flew EVERYWHERE, also jammed up behind the pully on the alt.not fun lol))

Check a/c compressor bearings

I'd bet it's the replacement alternator as well. Either the wrong model, improperly mounted, or you replaced it with a used one that had bad bearings to begin with.

Take that belt off and grab the alternator pulley. If you pull on it, is there a lot of back and forth play? Spin it with your hand and listen, does it make a noise? Turn it slowly and feel for resistance as it turns. -- Such things would point to bad bearings. For it to be making this much noise, the signs should be quite noticable.
When i read this thread I thought to myself , the noise wasn't present BEFORE the alt. was replaced so it means 1 of 2 things. You did something in the removal or installation of the new alt. to affect something in the vicinity of the workspace which now is making a noise, or the replacement alt. is bad causing the noise. I, too, would look at the alt. if it is still making noise, ( I sure hope not as over 3 months have elapsed since the original thread began.) Back in the beginning of January, I replaced the alt. in my father-in-law's '95 Chevy truck. It too was making noise and getting really hot to the touch real quick. I took it back to the store ,(Autozone) actually another one in my area as the original store was out of stock,and they tested it and found it to be defective. They bought out another one off the shelf and before I left the store had them test it to see if it was good. Well it too was defective as was the next one they had. They called another Autozone in the area and I went there and the first one they had was also defective, and finally the next one off the shelf was good. I figure it must have been a bad batch of alts. coming off the assembly line that day or something. I went through 5 alts. before I found a good one to re-install. I have come across instances like this in the past where the replacement part is also defective off the shelf. That is why when I read this thread that occurence came to mind. If you are still experiencing the noise, I'd have the alt. re checked just to rule it out.