What is the difference between R-134a and R-1234yf?
Short answer: R-1234yf is the newer refrigerant with a much lower global warming potential; it is mildly flammable and needs its own service equipment, fittings and procedures.
R-134a was the standard automotive refrigerant for many years. R-1234yf replaced it in most new vehicles because it has a far lower global warming potential. The two are not interchangeable, and mixing them contaminates the system and service equipment.
R-1234yf is classified as mildly flammable, so vehicles and equipment are designed with that in mind. Service machines built to the applicable SAE standard include features for its properties. The service fittings are different sizes from R-134a to prevent cross-contamination.
In practice, shops need equipment for each refrigerant they service, a refrigerant identifier to confirm what is in a system before recovering it, and technicians trained and certified under EPA Section 609. Work in a ventilated area, wear safety glasses and gloves, and keep ignition sources away when servicing any refrigerant system.
Tools used for this job
General guidance only. Follow the vehicle and tool manufacturer's procedures, and confirm vehicle coverage on the tool maker's list before buying.