1B-10 AIR CONDITIONING ON-VEHICLE SERVICE Precautions for Refrigerant -134a (R-134a) Air Conditioning System Legend 1. Refrigerant line 2. Cap 3. Evaporator This vehicle is equipped with Refrigerant-134a (R-134a) air conditioning system. R-134a and R-12 systems require different types of lu- bricating oil. Components designed solely for use with one refrigerant and oil type must never be interchanged with components designed solely for use with another refrigerant and oil type. R-134a Refrigerant: Service charge valve: The diameter of the service charge valve for the R- 134a system is made larger than that for the R-12 system to prevent cross-contamination.
In addi- tion, the screw-in type joint of the R-12 system is replaced with a quick joint type in the R-134a sys- tem. R-134a differs entirely from R-12 in its composition and, therefore, the two should never be mixed. Al- ways charge the specified amount of R-134a. The pressure characteristics of R-134a differ from those of R-12. The low pressure is lower, and the high pressure is higher. R-134a Compressor oil: The R-134a system requires a synthetic (PAG) compressor oil whereas the R-12 system requires a mineral compressor oil. The two oils must never be mixed. Compressor (PAG) oil varies according to com- pressor model. Be sure to use oil specified for the model of compressor.
Oil Specification ZXL-100PG (ISUZU PART No. 8-97101-338-0) The PAG compressor oil for the R-134a system tends to absorb moisture more quickly than mineral oil. When air conditioning parts are removed for servicing, all the open ends of parts and compo- nents must be sealed with caps to keep out con- taminants. N1A0057E To prevent refrigerant from escaping during instal- lation and removal of charging hoses from the ser- vice charge valves, quick-joint type fittings are used. Connection: Push on firmly until locked (a “click” will be heard). Removal: Hold the grip-ring and pull to remove. The PAG compressor oil must be stored in metal containers, not in plastic containers. N1A0056E N1A0058E