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What is the difference between a car air conditioning regas and a service?

When it comes to car air conditioning, to many people, the terms “regas” and “service” are synonymous, but this is not necessarily the case. 

A regas (or recharge) is done with a highly specialised machine that can evacuate, flush, recharge, and test the air conditioning system without releasing any of the old or new refrigerant charge into the atmosphere. 

Car air conditioning regas or recharge

A complete regas or recharge would typically occur after major repairs to the air conditioning system had been carried out. These types of repairs would include the replacement of major components like compressors, accumulators, receivers/dryers, or after any other procedures that could have allowed atmospheric air to enter the system, such as fixing major leaks.

Briefly, a regas involves evacuating the system to remove all oxygen and moisture, after which a precisely measured amount (by weight) of the correct refrigerant is introduced into the system, along with an amount of lubricating oil that circulates throughout the system to lubricate moving and/or rotating metal parts. In many cases, a special dye that fluoresces under UV light is also introduced to make it easier to spot refrigerant leaks later on, which brings us to an air conditioning system.

Car air conditioning service 

All car manufacturers recommend that the air conditioning systems in their products undergo regular inspections and servicing in order to ensure reliable and consistent performance. In all cases where vehicles are covered by warranty conditions, the manufacturer specifies very specific checks and procedures that must be carried out/completed to maintain the warranty. Specialist pressure gauges are used to check system pressures during an air conditioning service.

Below are some details of what is typically included in a comprehensive service that should take a minimum of one hour or so to perform:  

  • A thorough visual inspection of the entire system, including drive belts, pulleys, hoses, and the overall condition of the condenser. This step could also include a diagnostic check of the air conditioning system with a suitable scan tool
  • Checking system pressures in both the low and high-pressure sides of the system: note that depending on the results of this check, the system will be checked for leaks that will be repaired before the refrigerant charge is either topped off, or replaced
  • Operating the system to verify the correct operation of control switches, system pressure switches, thermostats, blower motor, and the compressor clutch
  • Checking the temperature of the condenser when the system is in operation

It should be noted that air conditioning refrigerant is not consumed during the cooling process, which means that if no refrigerant leaks are detected during the service and both the low and high-side pressures are within specified values, it should not be necessary to add refrigerant to the system.

Refrigerant charges are based on weight, and since the allowable deviations from specified charge weights are very small, adding or removing refrigerant to/from the system when it is not required can have serious negative effects on both the operation and reliability of the air conditioning system as a whole.   

Car air conditioning work is a specialist area and is highly regulated, so it is strongly recommended that you only have your car air conditioning system inspected and serviced by a reputable service provider.