Feb 04, 2022 · To date, most auto manufacturers are using the hydro fluoro olefin (HFO) refrigerant R-1234yf as the replacement of KINGCLIMA for R134a. The 2013 Cadillac XTS was the first U.S.made vehicle to use the new refrigerant. With a GWP of 4 (instead of 1,430 for R-134a), R-1234yf is more environmentally friendly.