So i have a 2002 impala LS with the 3.8l 100kmi. Love the car. However there is a noticible whining/whiring noise coming from the front right of the engine. Right where the serpintine belt is. The noise gets louder as you rev the engine.
I first thought it was a pulley bearing but the sound is intermitent. I had the water pump and belt replaced at about 94k miles. The AC still works fine and i dont notice any problem with the way the engine runs. I just have no idea what is wrong with it. Any ideas?

 

Have you looked into the power steering pump? It's very common for these to go out or make a loud whining noise. The more load (turning, increased throttle) you put on it the worse it gets. I found out that replacing with new doesn't always solve the problem cuz new pumps may have bad bearings just like your noisy one. I ended up pulling one from a junk yard and no longer have the noise.

 

In addition to the ps pump, take a close look and listen to your belt tensioner. They start making noise when the bearing starts to wear out on them. Did you check the fluid level in your ps pump.

 

A 2nd on the tensioner pulley.
I had a squeal on start up that went away after a few miles. When I spun the pulley by hand after removing the belt, it felt rough. Napa had a pulley with bearing for under $20. Noise was gone with new pulley. Just a heads up, the bolt that holds the pulley to the tensioner arm is left hand threaded. Don't ask how I know that.
Good luck.
E.