Whinning or Grinding noise-what is this?

[2-ECHO]

I have 1990 240sx with 137,000 miles...coming home last night, starting to hear like a whinning or grinding noise under hood. check all fluids, no leaks.....a/c turned off, still hear noise....anyone can tell me if this is a compressor problem, fan clutch problem,or any advice from you great warriors out there?

[slo40]

Did the pulley on your compressor lock up? And is it the sound of a belt slipping or something else?

[bcar240]

I had a similar problem, like slo40 said it turned out to be my belts slipping. it sounded kind of like a high pitched squeal. at first it only happened when the a/c was on, but as they got looser it started happening all the time. Check the tension and wear on the belts, if they are ok, check the pulleys.