Tag: ac compressor clutch

Is my ac compressor working ok

What components should be replaced to avoid any other problems with the new compressor?


  • Compressor
  • TXV(Thermal Expansion valve/FOT(Fixed Orifice Tube)
  • Receiver-drier / Accumulator
  • Seals at every connection open(O-rings /washers)
  • Condenser
  • Flush A/C lines
  • Balance compressor oil and A/C components replaced oil
  • Pull a deep vacuum
  • Recharge

The AC compressor should last for the entire life of the car, usually 8-10 years. Before installing a new air compressor we need to investigate what caused the failure in order to avoid future issues.

What causes an air compressor to lock up?

Lack of lubrication
Cooling system poor performance
Condenser fan not working or performing poorly
A/C system overcharged
Incorrect type of oil
Low refrigerant charge
A/C system contamination
A/C refrigerant cross contamination (Charging R-134a refrigerant into R-1234YF refrigerant.)
Inefficient condenser
Dirty evaporator core (In the past, not much attention was paid to dirty evaporators. Technicians are now beginning to realize that low evaporator pressures cause high compression ratios.)
The compressor’s efficiency can be improved by maintaining the correct working conditions. This involves keeping the suction pressure as high as practical and the head pressure as low as practical within the design parameters.
When a compressor begins to have an internal failure. It often releases debris into the A/C system. The debris created can be metal or Teflon. When enough debris is present, it can become trapped in the various components, and restrict the flow of refrigerant and oil.
After a catastrophic compressor failure the system must be flushed, otherwise the new air conditioning compressor could get damaged by all the debris released by the old locked up a/c compressor.
Most vehicle manufacturers recommend closed loop flushing with refrigerant as a flushing agent. A benefit of this type of flushing is there is no danger of flush contamination, since the flush agent being used is the correct refrigerant for the A/C system.

Fix what is causing the air conditioning compressor to fail.

Some common problems automotive a/c compressors may experience:
1-High head pressures, due to:
1.1-Overcharged ac systems.
1.2-Condenser fan not working at all or working not efficiently enough.
1.3-Clogged up with road debris, condenser core.
1.4-Contaminated a/c systems, with non-condensable gases.
2-Frequent clutch cycling due to:
2.1-Low refrigerant charge.
2.2-Faulty cycling switch.
3-Lack of lubrication or incorrect type and oil viscosity.
4-High resistance in clutch ground circuit.
5-Compressor bearing contaminated with other engine fluids (coolant, power steering…etc)

Auto ac compressor clutch assembly.Air conditioning compressor bearing

The compressor clutch will not disengage when the A/C control is switched to off.

A/C clutch coil shorted.

If the positive wire to the compressor clutch coil is shorted to a 12-volt source, the compressor clutch will not disengage. This is simply because there is no control of the power to the clutch.