Refrigerant: Description and Operation

Similar in function to the engine coolant, the refrigerant is the medium within the A/C system that absorbs, carries, and releases heat. This vehicle uses Refrigerant-134a (R-134a), a non-toxic, non-flammable, clear, colorless, and liquefied gas. While the R-134a A/C system is very similar to an R-12 A/C system, the differences in the lubricants and in the service equipment are important. R-134a carries a charge of a special lubricating oil, Polyalkylene Glycol (PAG) refrigerant oil. The GM PAG refrigerant oil has a slight blue tint. The oil is hydroscopic (water-absorbing) and required storage in a closed container.

Use only PAG synthetic refrigerant oil for internal circulation through the R-134a A/C system; use only mineral-based 525 viscosity refrigerant oil on the fitted threads and the O-rings. Use of any other lubricant may cause compressor or fitting failure.