What kind of refrigerant is installed on a 1988 Cadillac Coupe deville?
1988 Cadillac Coupe DeVille models most likely used R-12 (Freon-12) refrigerant in their air conditioning systems. R-12 was the standard refrigerant in automotive AC systems until it was phased out due to its ozone-depleting properties. Any R-12 found in a vehicle now is illegal to use. If the system needs servicing, it would require conversion to a compatible R-134a system with proper modifications.