I just noticed after running my AC and having my driver'* side window down (restaurant drive-through) I noticed that I'm having a rattling sound coming from under the hood. i turned the AC off to hear it better because the fan was on high, and the rattling went away. I turned the AC back on, and the sound returned. My question is if this can be expected of a compressor, or if it could be a sign of it going bad. Last summer I noted having an extreme loss of engine power with the AC on. It was almost unbearable how slow the car was with the AC on. I'm not noticing the same severe loss of power, but now the rattle is present from the compressor. Do you think it'* anything to worry about?