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Air Conditioning Systems

     This is just a general insight put in place to help owners understand what they don't normally come across every day in the repair & maintainence of their US GM vehicle.

     During the late 90's the Australian Government mandated that Automotive Air conditioning systems change over to R134a Gas from the older R12. This is also done to help people understand the reasons A.C. professionals need to charge a reasonable amount of time to do the job properly. It's not just a bolt it on and throw some gas in it.

     If your about to have work done on your US GM air conditiioning system, DO IT RIGHT. Change Filters, oil, get it flushed right etc.

Listed below will give you some indication of the need to do it right... From web site


RECOVER ANY R12 IN THE SYSTEM Remove all R12 refrigerant using approved recovery equipment.  When complete, the system must hold a vacuum for 5 minutes.  if the system shows a positive pressure after 5 minutes, repeat the recovery process.
REMOVE THE R12 MINERAL OIL* It is recommended that R12 mineral oil be removed from the system being retrofitted.  This can be accomplished by draining individual components or by approved flushing systems.
REPLACE THE ACCUMULATOR OR RECEIVER-DRIER Remove the used accumulator or receiver-drier and install a new replacement unit that contains desiccant designed for R134a systems. 
PERFORM SYSTEM REPAIRS Make necessary system repairs.  check the condition of expansion valve, orifice tube and pressure switches.  If bad, replace now,  Check engine cooling system performance (Radiator, fan and shroud).
INSTALL AN IN-LINE FILTER If the compressor is replaced, installation of an in-line filter on accumulator type systems is required to protect the compressor .
HIGH PRESSURE CUT-OFF SWITCH Installation of a high pressure cut-off switch may be necessary on some vehicles to insure compressor durability.
INSTALL R-134a SERVICE PORT FITTINGS Installation of R134a service port fittings is required by law.  
APPLY R134a LABEL Complete  retrofit label  and affix in a prominent position in the engine compartment.  This is required by law.
ADD R134a LUBRICANT Add the correct amount of A/C lubricant for the particular system that is being retrofitted.
EVACUATE THE SYSTEM* Evacuate the system for 45 to 60 minutes.
CHARGE WITH R134a* Determine the correct charge for the system being upgraded to R134a use.  In most cases, the R134a charge will be 10% less than the R12 charge.
PERFORM LEAK TEST Leak test the system using equipment that will detect R134a refrigerant.
ROAD TEST THE VEHICLE A 3-5 degree Fahrenheit increase in duct outlet temperature is not unusual.  Adjusting the clutch cycling switch to reduce the cutoff pressure by 2 pounds (maximum recommended adjustment) or the installation of an auxiliary condenser fan may be necessary to reduce the duct temperature on some vehicles.



The systems are generally, no different to any other older system. Not a problem untill you go to get a new compressor or have service work done on your AC system, assuming your car has not been update.

You can't mix both types of gas's. They damage the system. Starting with but not limited to the compressor.

If you have a system re-gassed and your compressor starts squeelling, your most likely damaged the compressors internals/bearing. Result will be a mechanic who deny's doing wrong, a (if new) compressor being rendered worthless and a new one needed.

When changing a compressor.. and /or  changing/charging gas systems.. DO IT RIGHT..



  * Proof of Lic AC professional required to be filed with us within 21 days of our supply for warranty to be valid.  We give NO WARRANTY on any compressor.. zero NONE - NIL, new or re-manufactured.  Any warranty is subject to the USA AC DELCO people inspecting the Compressor for likely manufacturing faults, if found damaged due to improper accessory component operation or lack of proof of Licensed AC professional install. Cost to express post to the US is to be prepaid, along with the carton it came in and extra packaging. It is up to you to get the Compressor to the U.S. in good order. We'll undertake to report back mutual copies of reports normally within 2 - 5days of US Delco receiving the compressor. At no time will we release another compressor or cover any costs. There are TOO MANY cowboys in the AC industry and too many people doing part of a job that Can Only Be Done 100%  or nothing.  Again .. we will not warrant or cover any compressor for any reason outside of transit loss or IMMEDIATELY notified transit damage along with proof of packaging damage, if also received damaged a courier claim needs to be made, that's why we cover everything with insurance.

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