Refrigerant R-134a

During A/C operation, the refrigerant circulates through the refrigerant system in order to absorb heat from the air being cooled and to send the heat to the outside. The refrigerant also carries a lubricant to parts of the compressor. Like the coolant in the engine coolant system, the refrigerant absorbs, carries, and releases the system heat. Although various substances are used as refrigerants, past automotive A/C systems used a type called R-12. This A/C system uses R-134a, a non-toxic, non-flammable, clear liquid or gas.