Important: The chart above is not a universal oil specification. Its quantities have not been verified for any specific vehicle. Do not use them to determine how much oil to add. Follow the vehicle and compressor manufacturers' specified oil type, total capacity, and component-replacement procedures. The image's right edge is cropped, so some instructions are incomplete.
An automotive A/C system works as a sealed circuit. Correct assembly means more than connecting parts: the components, seals, oil, and refrigerant must match the vehicle's requirements, and the circuit must stay clean and dry.
How the components connect
In a typical expansion-valve system, refrigerant travels from the compressor to the condenser, through the receiver-drier, and then through the expansion valve into the evaporator before returning to the compressor. Some components may be integrated into larger assemblies.
In a typical fixed-orifice system, refrigerant passes through the condenser and orifice tube into the evaporator. An accumulator sits on the low-pressure side before the compressor. The exact layout varies by vehicle.
Start with the correct parts
Compressor, condenser, hoses, metering device, and other replacement components must match the application. Verify the refrigerant and oil specifications using the vehicle manufacturer's service information. A part that physically fits is not necessarily compatible.
Keep the circuit clean and dry
Keep open lines and components capped until they are ready to connect. Dirt and moisture can damage the compressor, restrict refrigerant flow, and reduce performance. After a compressor failure, follow the prescribed contamination-removal procedure. Some components cannot be effectively flushed and may require replacement.
Seals, connections, and mounting
Use the specified refrigerant-compatible seals and replace them where required. Prepare and lubricate seals only as directed by the manufacturer. Align fittings carefully and tighten them to the specified torque rather than by guesswork. Support hoses and wiring away from hot surfaces, sharp edges, and moving parts.
Balance the compressor oil
Check the oil type and quantity supplied with replacement components. Follow the vehicle and component manufacturers' oil-balancing instructions. Too much or too little oil can cause problems, and a replacement compressor's prefilled amount may not match the system's needs.
Learn about automotive A/C oil and PAG 46
Checks before charging
A trained technician should check the assembled system for leaks using the specified procedure and suitable equipment, evacuate it to remove air and moisture, and charge it with the specified refrigerant mass. Holding vacuum alone does not prove that a system is leak-free. Never use oxygen or compressed air to pressure-test a refrigerant circuit.
Confirm operation
After charging, verify cooling performance, system pressures under the specified conditions, condenser airflow, controls, and leaks. Abnormal noise or poor cooling needs diagnosis rather than extra refrigerant added by guesswork.
This page is an overview, not a vehicle-specific repair procedure. Refrigerant must be recovered with appropriate equipment rather than vented. High-pressure refrigerant and electrically driven compressors require appropriate training and safety precautions.
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