With my climate system, the AC compressor will attempt to run even when the heat is on, unless you press the Econ button. I usually run in Econ mode to get better gas mileage, and the controls will eventually "learn" that you like to do that, and it will do it automatically.

I was just fooling around with it today, and I happened to be idling with the window down, I turned the Econ off, and heard/felt the compressor kick in, the I pushed the Econ button again, only to have the compressor disengage and hear a lovely grinding noise.

It eventually seemed to go away, although not that I think about Ive been hearing quieter versions of this noise occasional for quite some time.

With the hood popped, you can see the AC compressor pulley and then an area inside the pulley that doesnt turn unless the compressor is engaged. It almost looks like this area is pushing far enough away from the spinning pulley. The noise sounds like metal on metal grinding, and you can see a few little metal shavings here and there.

From the sound of things, the only way to fix it would be a new compressor, and Im not overly fond of that thought.

Ideas?

I know what you mean and hate the fact that I have to paush the A/C off button when cold outside or the car seems to cycle back and forth between the heater and A/C. Dumb idea. I dont know alot about A/C compressors other than I hate to change them but have been told more than once it is bad to run them when it is below freezing out and always wondered if that was true.

ALL cars that are equipped with air conditioning will cycle the compressor on when the defrosters are selected. This is done to remove the moisture from the windshield. Air conditioning has a two-fold purpose: to cool the air, AND to remove the moisture from the air.

When the defrosters are on, the system is telling the compressor to engage to remove the moisture from inside the car. Cars that don't have air conditioning will take longer to defrost the windshield.

IMO, it doesn't sound like there'* anything wrong with your car. However, can you get us a video clip of the noise?

Yes I know theres nothing wrong with the car, the compressor functions as its supposed to, when it supposed to, except when I turn it off. Because it bogs down my engine and hurts my gas mileage.

I did do some further research, and I found that with the car off, I can take my hand and turn the front of the compressor and it makes the same grinding noise as it comes in contact with the pulley, but not as loud because my hand can only spin it so fast.

I took some WD-40 and sprayed where the pulley comes into contact with the "thingy" and it quieted it down a lot, its practically gone now, but it does pop up once in a while. Im going to try and crawl under there at some point and put some actual grease between the two surfaces, something that will last longer than WD.

I just wondered if anyone had ever experienced this before, its just loud, and not in a good way, makes my car sound like its about to explode just sitting there.

The compressor bogs down my engine horribly too. I don't like to drive with my defrost on even because I can feel a HUGE difference in performance. In the summer with the AC on, it'* almost unbearably slow. :( I don't know if it'* a common problem with our compressors or not though.

yeah, I know exactly what you are talking about... I had the same problem with several cars: 1995 cavalier ( I eventually got sick of the noise and bought a serp. belt for it without a/c to bypass it) 2001 cavalier and 2002 *-10 zr2. my brother also has the same problem with his 1999 grand am, I have no clue what is causing it, but it sounds as if the compressor clutch is not fully disengaged. :?