Q: How do you properly remove and install an A/C compressor following the manufacturer's instructions on BMW X5?
A: Following manufacturer's instructions, connect an approved refrigerant recovery, recycling, or recharging unit to the A/C system and discharge system. Raise the car and support it safely, then remove the splash shield from under the engine. With the engine fully cooled off, drain the cooling system. Mark the A/C drive belt with the direction of rotation and remove it. Remove the air filter housing. Working above the right front of the engine compartment, squeeze the plastic junction at the secondary air valve to separate the air intake hose and tie it to the side to gain access to the A/C compressor. Remove Allen mounting bolts and pull off refrigerant lines, plugging them and the ports immediately to prevent contamination. Detach the coolant hose from the right side of the thermostat housing. Working underneath the vehicle at the radiator outlet hose, detach the radiator outlet coolant temperature sensor, then detach the coolant hose from the radiator and remove it, along with the mounting plate underneath the radiator. Underneath the vehicle, detach the compressor electrical connector, cover the frame rail underneath the compressor, remove the compressor mounting bolts, and lift out the compressor with refrigerant lines attached. Separate the lines from the compressor on a workbench, ensuring to replace sealing O-rings when reattaching refrigerant lines. Installation is the reverse of removal, with sealing O-rings replaced when reconnecting refrigerant lines. If installing a new compressor or if the compressor is off the vehicle for more than 24 hours, replace the receiver-drier unit. Install and tension the NC drive belt, noting the previously made direction mark. Fill and bleed the cooling system, then recharge the NC system following the equipment manufacturer's instructions. When starting a new compressor for the first time, switch on the NC system, set air vents to OPEN, start the engine and allow it to idle, set blower output to 75% of maximum, and run the NC for at least 2 minutes at idle speed (under 1500 rpm), as the new compressor may be damaged if run at higher than idle speed at start-up.