Vehicle Damage Warnings

Solubility of refrigerant oil
A required special refrigerant oil Polyalkylene Glycol (PAG) synthetic oil is used to lubricate cylinder walls and bearings and enters the A/C system to some degree. This oil is NOT compatible with mineral based oils used in R-12 systems.

NOTE: R12 refrigerant systems use mineral oils which are not dissolved by R-134a refrigerant and are unusable.

Effects on plastics
Refrigerant R-134a will deteriorate some plastics. When system temperature drops, these plastics can be deposited at the expansion valve or restrictor causing blockage. Therefore, when making system repairs, use only genuine Audi replacement parts which are specified for use with R-134a refrigerant.

Effects on metal
In its pure state, refrigerant R-134a is chemically stable and will not attack iron or aluminum. However, the mixture of R-134a and PAG oil may deteriorate certain metals (copper) which could lead to blockage, leaks or deposits on the compressor piston. Therefore, when making system repairs, use only genuine Audi replacement parts which are specified for use with R-134a refrigerant.

Water solubility
Liquid R-134a refrigerant will absorb only very minute quantities of moisture. However, R-134a vapor can absorb large amounts of moisture.

Water in the system forms ice in the expansion valve or restrictor causing the system to stop cooling. In addition, moisture combines with the refrigerant to form acids which will damage the system.