64 52 Notes for changing the air conditioning compressor (refrigerant oil level of new air conditioning compressor not known)

A DIFFERENT PROCEDURE  applies for air conditioning compressors with a label indicating refrigerant oil level.

Remove the air conditioning compressor without damaging and without the use of force! 

Air conditioning compressors with plastic belt pulleys: 

• Avoid impacts/knocks to plastic belt pulley (caused by tools, contact with base).
• Return faulty air conditioning compressors in their original packaging only.

• Switch on air conditioning
• Set all nozzles in the dashboard to "OPEN"
• Start engine and let it stabilize at idle speed
• Set blower output to min. 75% of max. blower output
• Switch on air conditioning and run for at least 2 minutes at idle speed 

Risk of damage at increased engine speed! 

In the event of a mechanical air conditioning compressor failure and the resulting ingress of chips into the refrigerant circuit, replace the following parts: 

All vehicles: 

• air conditioning compressor
• Replace desiccant insert
• Line to the capacitor
• Refrigerant oil

The new air conditioning compressor is filled with refrigerant oil at the factory.

The refrigerant oil level in the new air conditioning compressor corresponds to the refrigerant oil level for the entire new and unfilled  refrigerant circuit.

When replacing the air conditioning compressor it is absolutely essential to adapt the refrigerant oil level in accordance with the instructions below! 

The only time it is not necessary to adjust the refrigerant oil level is when replacing the entire  refrigerant circuit.

When evacuating the air conditioning system, refrigerant oil is also extracted and collected in the oil separator of the A/C service station.

After suction process, the refrigerant must be filtered in the A/C service station as the oil separator could still contain a liquid refrigerant/oil mixture. The refrigerant completely gasifies through the cleaning operation. Only the prior bound refrigerant oil remains in the oil separator. Measure and note down this quantity of refrigerant oil.

Fig 1: Evacuating Air Conditioning System

Courtesy of BMW OF NORTH AMERICA, INC.

Refer to EVACUATING A/C SYSTEM .

Transfer the refrigerant oil remaining in the previous air conditioning compressor via the oil filler plug completely into a measuring cup.

Fig 2: Pouring Refrigerant Oil

Courtesy of BMW OF NORTH AMERICA, INC.

Measure the refrigerant oil level collected from the previous air conditioning compressor.

Fig 3: Measuring Refrigerant Oil Level

Courtesy of BMW OF NORTH AMERICA, INC.

Open oil filler plug and pour entire contents of air conditioning compressor into a clean collecting vessel.

Tightening torque: 64 52 2AZ

Fig 4: Pouring Air Conditioning Compressor Into Clean Collecting Vessel

Courtesy of BMW OF NORTH AMERICA, INC.

From the new air conditioning compressor, pour out the same amount of coolant (as drained from the previous air conditioning compressor) + 10 ml extra  into a clean measuring cup and pour again into the new air conditioning compressor. At least but a total of 50 ml. 

Remaining refrigerant oil can be poured into A/C service station tank.

Refer to EVACUATING HEATING AND AIR CONDITIONING SYSTEM .

Otherwise the excess refrigerant oil must be disposed of correctly.

On user account of its hygroscopic properties, refrigerant oil must not be stored in open containers.

Fig 5: Pouring Refrigerant Oil Into Open Containers

Courtesy of BMW OF NORTH AMERICA, INC.

The refrigerant oil drawn off from the oil separator of the A/C service station and from the previous air conditioning compressor must not be reused and must be correctly disposed of.

Fig 6: Pouring Refrigerant Oil

Courtesy of BMW OF NORTH AMERICA, INC.

After installing the new air conditioning compressor, it is essential before filling the air conditioning to pour the same amount of the previously drawn off refrigerant oil into the system again.

Refer to EVACUATING HEATING AND AIR CONDITIONING SYSTEM .

Fig 7: Installing Air Conditioning Compressor

Courtesy of BMW OF NORTH AMERICA, INC.

Installation note: 

If the refrigerant circuit is open for longer than 24 hours: Replace drier bottle/drier insert.