My compressor just started the grinding / metal-on-metal noise recently. One of the "Celtic" metal hoops on the front of the compressor broke and I think it's causing the drive plate to tilt inward & rub. I just ordered a new OEM one the other day & plan to "hopefully" make the repair in place w/o removing the compressor. I expect this should fix it. If so, I think it should be a relatively cheap fix for around $70....