Hi:

When I turn the AC on I can here a grinding noise like a "rrrrrrr" coming from the area where the belts are. When I turn the AC off the noise goes away.

What could this be?

Thanks!

I would assume it is either the air compressor or the air compressor clutch. Your compressor isn't engaged (running) until you push the A/C button inside the car. Once you turn it on, the a/c clutch links the pulley that the belts are spinning and the compressor. This then causes the a/c compressor to spin internally. My car is doing the same thing. I am going to bend over and take it to the dealership. I am sure they will just want to replace the entire air compressor which will probably be expensive. You might be able to just replace the clutch though. I don't know enough about it to tackle it. Good luck.

So I can probably keep on driving my car without turning the AC on?

My compressor made a similar noise for about 7 months. The A/C worked fine, the compressor was just noisy. It got a little worse so I replaced the compressor. 250 for a remanufactured compressor at Auto Zone and 150 for the install. This one is much quiter, however not as quite as I would like. I think a lot of Maximas have noisy compressors. Hope this helps.

I don't know if I'd advise that. Here's why - it could be possible that whatever is grinding may seize and lock up. If that were to happen your belt would heat up and break, possibly leaving you stranded. I would get it properly diagnosed and re-evaluate from there. Hope this 2 cents helps. Good luck. Mine goes in for service next Wed. I'll let you know what they say about mine.