What kind of freon 1992 cadillac sedan de ville take?

There is no such thing as freon 1992. Freon is a brand name for a variety of chlorofluorocarbons (CFCs) that were widely used as refrigerants and aerosol propellants. However, CFCs have been banned in most countries due to their harmful effects on the ozone layer. The 1992 Cadillac Sedan DeVille likely uses R-12 refrigerant, which is a type of CFC. However, it is possible that the car has been converted to use a more environmentally friendly refrigerant, such as R-134a. You can check the owner's manual or contact a qualified mechanic to find out what type of refrigerant your car uses.