Vehicle Damage Warnings

R-12 and R-134a refrigerant are not compatible. Never add R-12 refrigerant to an R-134a system or refrigerant or R-134a to a R-12 system. If the refrigerants are mixed, total system contamination will occur and compressor failure may result.
Refrigerant oils used for the R-134a system and R-12 system are also not compatible. Use only the specified synthetic oil Polyalkylene Glycol/PAG for the R-134a refrigerant system. Do not use R-134a system oil in the R-12 system or R-12 oil in a R-134a system. If the oils are mixed system contamination will occur and compressor failure may result.

R-134a refrigerant system oil (PAG oil) absorbs moisture very rapidly.
Moisture combines with the refrigerant to form acids which will damage the system. Use only the specified oil from a sealed container and always reseal oil container immediately after use. Do not use oil that has been contaminated with moisture. Immediately plug open connections on A/C components to prevent dirt and moisture contamination. Like wise do not remove new components from packaging until ready to install. Immediately tighten components after installation.