Why do compressors fail?

HyChill Australia is the leading manufacturer and supplier of refrigerants to the automotive aftermarket. HyChill Minus 30 is a superbly efficient air conditioning refrigerant that delivers an array of benefits to the motorists, ensuring that they continue to travel in comfort during the hot summer months whilst avoiding negative environmental impact. HyChill’s experience in the field of car air conditioning is unrivalled, which is why it is often being approached by car mechanics and technicians for technical advice. Today, HyChill’s Colin Spencer talks about one area of special interest to many mechanics: why do compressors fail?

“In most cases the reason you are fitting a reconditioned and guaranteed compressor is that the old or original compressor has “GONE DOWN”, therefore you must ask yourself why did this happen?”, asks Colin.

“Compressors do not fail for unexplained reasons so be assured that if you fit a compressor without answering the “WHY” question and without following the correct installation procedure this compressor will also “GO DOWN” causing you unnecessary losses in both time and money.”

So, why did the old unit fail?

The three most likely causes for compressors to seize:

1. Excessive head pressure

Underlying cause

  • Blockage in the system
  • Overcharge in the system
  • Overpressure in the system


  • Check dryer, TX valve and the condenser (internally)
  • Reduce charge (some compressors are very susceptible to this issue)
  • Inadequate car cooling system, clogged condenser fins (external), defective thermo fan or fan clutch, excessive moisture in system, a cocktail of refrigerants

2. Lack of oil

Underlying cause

  • System blockage
  • System leak


  • Check for restrictive flow of oil back to the compressor (i.e. TX valve, receiver/dryer, condenser, freezing evaporator)
  • Check for a leak allowing oil to escape from the system

3. Lack of refrigerant (compressor overheating)

Underlying cause

  • Undercharged system
  • System leak


  • Slow leaks allow the system to run with low liquid supply to tx valve. The suction return gas to the compressor is not cold enough to cool the compressor parts internally. Shaft seals harden and leak, oil deteriorates and metal parts fail

Once you have found and rectified the reason for the old compressor failure, follow this procedure for the installation of the new unit to ensure trouble free running.

Installing the new unit


It cannot be stressed strongly enough that if a compressor has had a burnout depositing sludge and debris through the system, this sludge will simply work its way back to the compressor if it is not removed.




Of course, the easiest way of reducing load on the compressor is to recharge it with a hydrocarbon refrigerant such as HyChill Minus 30, which operates at a lower pressure.

“But wait, here is one more benefit of HyChill’s Minus 30”, says Colin.

“When compressor oil is replaced it normally needs to match the refrigerant being used. Well, HyChill SRO 500 lubricant is compatible with all refrigerants and HyChill Minus 30 Refrigerant is compatible with most commonly used oils. Yet another easy solution for happy motoring!”