I was adding refrigerant to my ac and as i turned the can sideways the psi went to ~50(top of full, bottom of alert, it says 45-55 is correct charge for this ambient temp) the engine made the noise brakes make the first time theyre used after going through deep water and the engine went down (from 1k to 600,in park). when i drove it around the block it made the grinding noise intermittenly and felt like it was trying to slow the engine down, and it went down to again 600 rpm when i was backing up. the air seemed to stay cold the whole time but the noise went away and it drove normally with the a/c off. is the compressor blown?