Air Conditioning Retrofit R12 to R134

Auto air conditioning can easily be changed from old R-12 to new R-134 refrigerant. The new style R-134 refrigerant can be used in R-12 systems as long as the oil is included with the installation of the new refrigerant. No new seals or any other components should need to be replaced. Your car’s system should be completely empty of the old R-12, which is supposed to be contained and removed by a certified refrigerant technician. When doing anything with ac you should first understand that there are two sides of the system. The high pressure side will be the side with the smaller diameter lines, this side is very high pressure and should be avoided. The low pressure side will have the larger diameter lines and will have the condenser. The condenser looks like an aluminum canister of about 4″ in diameter and appx. 6″ long. The fill port will probably have a plastic cap on it. The port is a valve that looks like a air fill on your car tires. You will need a kit composed of an adapter and the hose used to fill the system with. Some types of cars need different adapters.

 

It is always a good idea to have a gauge present to test the pressures with, as you install the R-134 refrigerant. First find out how much refrigerant your system is meant to hold. Once you know this number, you can buy as many cans of refrigerant as you will need to fill the system. The cans are normally 12 oz. which means you will probably need three and one can of oil. If you forget to buy a full size can of oil your compressor will become damaged. Start with attaching the adapter to the low pressure side fill port. This will allow you to quickly connect and disconnect the fill hose. Next start with the refrigerant oil first. Find the side of the hose that the can will screw on to. First rotate the screw device on that end of the hose all the way out. Next screw the can onto the hose and snap the other end onto the adapter fitting. Rotate the screw device clockwise or in then counter-clockwise or out to release the oil into the ac. Start the vehicle and turn on the ac. Don’t be alarmed if there is no cool air even as you add coolant. There is a pressure switch and the compressor won’t work until a minimum amount of coolant is reached. It may take a while for the can to empty out, you will know it is because the can will become very light when empty. A small amount of pressure will escape every time the line is disconnected, this is normal. Repeat this same process with the refrigerant cans now. Usually the compressor will kick on after approximately three cans total. After the compressor first kicks on, the system will usually take about one more can to be filled up. This is a good time to use a pressure gauge made for automobile air conditioning systems. Verify that the pressure is not too high, if it is, carefully bleed a little pressure off, keeping your skin away from the fill port. To bleed some pressure off, shut off the car and use the hose without a can attached. Quickly press down on the fill port with the hose end and some pressure should be released. Some import cars also use a nice air conditioning feature. They will have a glass “window” in the condenser. The fluid in the window looks bubbly until enough coolant is in the system, it will then look clear. Your car should now be blowing cold air. Be careful to not overfill the system and to use the correct low pressure lines. Not following the procedure or guessing could cause an explosion so educate yourself first and take your time.