I have a used 2002 Impala 3.4 . Theres a strange noise coming from my pulley and alternator area, but goes away or at least quiets when ac is on. What exactly is it, and how can I fix it?

I watched a YouTube video about both answers, and the noise is similar to a bad pulley. The alternator still has a sku barcode, so I guess its pretty fair.The sound is like almost a scraping, shook spray paint can, until the ac is on.

It also may be the A/C compressor pulley. Have both checked.

I intend to, just dont want to spend money on top of money for one problem.

Your alternator is on one side of the engine, the A/C compressor is on the other side. By listening, see if you can isolate the sound location. If you put a load on the A/C unit and the sound goes away, chances are that is where the sound is coming from. It just may be as simple as replacing the compressor clutch, much less than the entire unit. If it is from the alternator, a new one may be necessary to replace unless you can find someone to change out the bearings for you. If it is the belt idler pulley, it is a cheap and quick fix. Don't throw money onto hoping to guess the problem, isolate it, and eliminate others.

Ok. The 02 Imp is W-Body FWD, so the alternator and pulleys are paralell to the passenger side meaning the engine is sideways. The sound is not hissing or whirring though. All noise is from the left in the front. Engine not smoking at all.So its a variety of things to eliminate.

If a bearing is going out in the A/c compressor, it will rattle until a load is placed on it. It will sound like a little pea inside a paint can. Ok, stand on the passenger side of the engine and see if you can eliminate the sound coming from the alternator. Have someone inside turn on and turn off the A/c controls and see if the sound is isolated from the A/C compressor. From the information you are giving us, it sounds like either the idler pulley is going out or the A/C compressor due to the rattle going away when it is engaged. It is under warranty? Let the dealer worry about it. If you can isolate it, that will help in getting them to fix it. Be careful by looking at the 3,000 mile warranty and make sure the A/C unit is covered. Some warranties do not cover it.

Thanks fellas. This is my first Chevy, and Ive been hearing that this particular model has been a pain to maintain. When o get a break from work, ill first go to AutoZone to be thorough, not that im ignoring you giys advice and send the diagnostics to the dealer. If these are the problems , Ill let ya know.

Why not take it to the dealer right away? If someone else works on it, it may void the warrany. I always to with the warranty first to save money. Just saying.

Thinking about after Labor Day. Ill be off work a few days. The dealer told me to take it to Auto Zone first, havent had time because of work.

Have a nice holiday. I have to go out of state this weekend and not back until the middle of the week. Be safe my friend.

Just want diagnostics. If I buy the part, labor is no charge. I cant go anywhere alone, unless someone has licence. Ga law says EVERYONE who has class CP cannot drive alone until they pass driving test. I still have like 2700 miles to go. Haha.

I've had 2 impalas and I think your catalytic converter could be clogging up. It has a diaphragm that chirps like a belt when it's going out.