To remove the automotive A/C Compressor, the refrigerant must first be discharged by a technician. The negative battery cable should be disconnected and the front of the vehicle raised and supported on jack stands. The drive belt, upper mounting fasteners, refrigerant lines, wiring connector, and compressor lower mounting fasteners should then be removed. If a new compressor is being installed, the oil level must be adjusted by draining the old compressor and calculating the amount needed for the new one. To install the new compressor, O-rings should be replaced with new ones and lubricated with refrigerant oil. Finally, the system should be evacuated, recharged, and leak tested.