[GTP Dad]

The problem may actually be with the AC compressor. When the engine runs and the AC is on the clutch engages and causes the compressor to turn. When it is not on the compressor pulley still turns and that may be where the noise is coming from. When the clutch engages it puts torque on the bearing eliminating the noise. It is ok to drive with the AC on all the time but power and mileage will suffer. Eventually you will need to have it repaired anyway. You may be better off to purchase a used AC compressor and get it changed. Don't try to do this yourself as you will need to evacuate the system and pull a vacuum on it before recharge.