An AC system has many components: compressor, condenser, receiver dryer, evaporator, and hoses. The compressor, the “heart” of the car’s air conditioning system works like a pump taking refrigerant, (R-12 in older cars, R-134a in 1995 and newer cars) and pressurizing it, passing it along to the evaporator.
The AC compressor has several moving parts (including pistons and valves). These internal parts can fail, causing the AC compressor to stop working. It is common for the internal parts of the compressor to come apart and disperse metallic debris throughout the system. Consequently, it is a requirement to replace the orifice tube and the receiver dryer when replacing the compressor since some of the debris may have ended up there.
For an AC compressor to work, it needs a clutch, bearing, and an electrical connector. The clutch is driven by a drive/serpentine belt, which engages the compressor when you switch on the AC. The clutch can burn or the bearing can fail. If the bearing or clutch have failed, it is recommended that the compressor be replaced. Sometimes replacing the entire compressor with a remanufactured one can be cheaper than replacing an individual clutch or bearings.
It is also common for the seals in the AC compressor to go bad. The compressor may start leaking refrigerant and/or the AC oil. If the seals no longer hold, you will need a new compressor, as the seals cannot be replaced. A compressor may also fail if there is sludge or debris in the air conditioning system. If there is sludge or debris, the hoses, evaporator, and condenser should be flushed to get rid of the contaminants. When it is not possible to flush the parts, you may need to replace those parts.
Keep in mind:
This service comes with receiver dryer and orifice tube. It is very common for metals from the compressors to go throughout the system and get caught in different components. If the compressor is replaced without the dryer and the orifice tube, it will ruin the new compressor and it will not be covered by the warranty from parts manufacturers.