Folks:

I had the A.C. charged and the initial little things done on 83 300SD, 160K miles. Intermittantly, I get a howling noise almost like something is functioning without any lubrication under the hood. I hear it at idle and it doesn't immediately stop when I shut the air off. It is intermittant, so it stops.

I think it's A.C. related because when I run without air at all, I get no noise even starting at all.

What's happening, compressor about to go? I'm inclined to just replace the compressor???