Sometimes when I turn on my A/C or defroster I hear a squeeling noise. I believe that it is the A/C compressor. I know that eventually I will have to replace it, but I am wondering if there are any temporary fixes for this, such as greasing it up or tightening something or other.

 

Take a look at your drive belts first. Check for cracks, too much deflection, and other signs of wear. I suggest this because when you engage the compressor, the drive belt is subjected to more stress and yours may be nearing the the time for replacement/adjustment.

 

I just replaced my drive belts about 2 weeks ago.

 

Check your deflection. It should be about 1/8 or so. I replaced my belts a few weeks ago and had to adjust the deflection about two days later. I didn't tighten the idler pulley bolt enough and it slipped just enough to make a slight squeal. It doesn't squeal at all now.

 

Once you install a new accessory belt you need to retension it after it has been broken in.

 

Now when I hear the noise there is a slight smell. Its very subtle and hard to describe, but its definatley there. Once again, this only happens once in a while, and seems to happen more on muggy/humid nights.

 

It's definitely your belts. I have the same exact issue on those muggy and slightly muggy days and I know its my belts because my belt tensionor is busted (no bolt) and that would explain the slack on my belts. The AC compressor is burning the belts when you turn it on, so you better adjust the pulley asap. Hope my experience helped.