R12 is a coolant widely used in the air conditioning systems of vehicles manufactured prior to 1995. Beginning in 1995, all vehicle manufacturers began using the EPA-approved alternative, R134a. When older vehicles need service to the air conditioning system, the usual practice is to change the system to the updated R134a coolant. This process can be completed almost entirely in the driveway and without tools. You can buy R134a conversion kits at your local auto parts store for far less than you would pay a professional. However, you must first take your car to a certified AC repair shop to dispose of any leftover R12 in your car's system.
Dispose of any leftover R12 in the system by taking the vehicle to a certified AC repair shop. Have the mechanic use a refrigerant recovery system to recover the R12 from your system safely. It is against the law to let the Freon into the air.
Take the car back home and park it on a level surface. Attach the adapter, included with the conversion kit, to the high-pressure outlet. The high-pressure outlet is located between the compressor and the condenser. Screw the adapter onto the port and finger tighten. Over tightening the adapters could damage the ports.
Attach the hose from the conversion kit to one can of R134a refrigerant. Twist the T-valve to puncture the can and start the Freon flowing into the hose. After about five seconds, turn the T-valve off and connect the other end to the low-pressure adapter on the air conditioning system.
Open the T-valve to allow the Freon to flow into the system. The ideal amount of R134 is up to 90% of the original R12 amount. Consult your repair manual for the exact amounts for you vehicle.
Allow the can to empty. Or, when you have reached the correct amount of Freon, twist the T-valve closed and unscrew the other end from the low-pressure adapter. Check that the air in the car is cold.
Cover the new adapters with the included plastic caps. Put the R134a sticker in the engine compartment where it is highly visible.
