Frequently asked questions

Q	Can I put R134a in an R12 system?
A	NO, R134a has a different molecular structure to R12 which necessitates the use of different flexible hoses and seals. The compressor may not be suitable (materials within it may not be compatible with R134a or its lubricant), and the service connectors are of a different design.

Q	Can I use mineral oil in R134a systems?
A	NO, mineral oil as used in R12 systems will not mix with R134a and will lead to compressor seizure due to lack of lubrication. Most R134a systems use Polyalkylene glycol (PAG) oil, but some may use the alternative Ester oil.

Q	Can I use PAG oil in R12 systems?
A	NO, if PAG oil is used in an R12 system it will cause corrosion and long-term damage.

Q	Can I re-use a receiver/drier or an accumulator/drier?
A	Yes, providing the system has NOT been open to the atmosphere, had a major component failure or been subject to contamination, it will probably be serviceable. However if any major repairs or replacements are carried out to the refrigerant circuit, it is advisable to change the unit.

Q	Why do manufacturers advise the use of the air conditioning system all year round?
A	If the system is not used for a prolonged period of time, the seals in the compressor will become dry and leak. The AC system also de-humidifies the air, when used in conjunction with the heater's defrosting function it will extract excess moisture from the passenger compartment air resulting in more efficient demisting.

Can I charge an air conditioning system with R12?

NO, from January 2001 the use of R12 has been prohibited. A proprietary 'replacement refrigerant' may be used or the system will need to be modified to allow the use of R134a.
Many replacement refrigerants are available but they may have different pressure/temperature relationships and may make fault diagnosis difficult.
Some replacement refrigerants may contain a percentage of liquid petroleum gas (LPG) and could be considered dangerous in an automotive application.
The use of alternative refrigerants may affect the system performance and the manufacturer's warranty.

Q	Do I need to have qualifications to work on air conditioning systems?
A	NO, but it is strongly recommended that only properly trained and equipped personnel service and repair AC systems.

Are there any special precautions to be observed when working on a vehicle with air conditioning?

Yes, the AC system is always under relatively high pressure and when operating, its components can be either very hot or very cold.
Ensure that NO dismantling of the refrigerant circuit is undertaken unless it has been evacuated with special equipment.
Never allow liquid refrigerant to touch skin as it will cause severe blistering (frostbite).
Never drain refrigerant in areas with poor ventilation (such as inspection pits) as it will sink to the floor and spread out, with the risk of asphyxiation.
Never smoke or use a naked flame in an area containing refrigerant gas, as high temperatures cause the gas to change into toxic substances.

Q	Can welding repairs be carried out in the vicinity of AC components?
A	Yes, but ensure that all components are shielded from excessive heat or direct flames.

Q	Can I evacuate the system by depressing the Schrader valve or loosening a fitting and releasing refrigerant to the atmosphere?
A	NO, although R134a, unlike R12, does not deplete ozone, all refrigerants damage the environment by adding to global warming. In most countries it is also an offence to 'deliberately discharge environmentally damaging refrigerant to the atmosphere'.