How to Add R134 to Vehiclesby Contributing Writer; Updated June 12, 2017
Automobiles were originally manufactured to meet the basic transportation needs of the automobile consumer. Vehicles comfort features were not available. Today, comfort features Vehicles the motoring public have become as important as a Vehicles reliability and performance. Adding or "charging" a Vehicles air conditioning system can be performed with basic automotive repair knowledge.
Under The Hood:
Secure the low-side service hose onto your container of R134a. Keep the valve closed on the service hose.
Locate the low-side quick disconnect valve on the accumulator hose. Again, the valve measures 13mm and connects to the silver hose extending from the accumulator. On most BMWs, the accumulator is on the passenger side and it is a silver tube with two hoses coming out of it. One side is the low-side hose and the second is the high-side hose. The valve is on the low-side hose.
Remove the cap from the hose and press the other end of the service hose onto the low-size valve. It is a quick disconnect valve so the hose will snap on just by pressing it onto the valve.
Turn on your BMW and turn on the air conditioner. Open the valve on the service hose and charge the air conditioner until the pressure gauge on the service hose reaches between 35psi and 40psi.
Turn off your BMW and disconnect the service hose from the low-side valve. Place the cap on the valve to complete the job.
Items you will need
Locate the air conditioning compressor on the front of the engine block. It is located on the top left of the engine compartment. There will be two hoses coming out of the back side of the compressor. One hose is the "high" pressure side and the other hose is the "low" pressure side of the air conditioning system. R 134 will be added to the "low" pressure side of the air conditioning system.
Follow each hose from the compressor until the "low" side fitting is reached. The fitting looks like the valve stem used to add air to a tire. There will be one fitting on each hose coming from the compressor. The "low" side fitting is larger than the "high" side fitting.
Remove the cap from the "low" side fitting by turning it counterclockwise by hand.
Attach the connector on the R 134 container hose to the "low" side compressor hose fitting. R 134 refrigerant containers can be purchased with a disposable hose, connector and pressure gauge.
Start the vehicle engine and turn the air conditioner on "max" and the blower on "high."
Puncture the top of the R 134 refrigerant container by turning the valve on top of the container clockwise until the valve is fully seated, then turn the valve counterclockwise to start the flow of R 134 refrigerant. Hold the R 134 refrigerant container upright during the charging process.
Watch the refrigerant pressure gauge on the refrigerant container. Continue adding R 134 until the needle on the pressure gauge is in the "green" range. Turn the valve on the top of the container clockwise by hand until the valve is fully seated to stop the flow of R 134 refrigerant.
Remove the refrigerant container hose connector from the "low" side fitting on the compressor hose. Install the cap on the "low" side of the compressor hose fitting. Make sure the cap is fully seated.
Items you will need
R 134 refrigerant
Put on your safety glasses, and screw the kit onto a can of refrigerant, first making sure that the rubber seal inside the threaded portion of the kit is securely in place.
Remove the protective cap from the low-pressure charging port, which sits on the large low-pressure line between the compressor and the evaporator, and attach the quick-connect fitting to the kit's hose. On a 1996 Cherokee, the port can be found right by the plastic coolant recovery tank.
Turn on the air conditioner, and allow the engine to warm up. Remember to keep the charging hose away from any moving parts.
Pierce the can open by turning the valve handle on the kit, then back it out again to allow the refrigerant to pass through. If the compressor cycles off, remove the connector from the accumulator, and hook up a jumper wire with alligator clips between the terminals to keep it engaged.
Add refrigerant until both the surface of the accumulator and the inlet pipe from the evaporator feel about the same temperature. The accumulator is a metal canister located on the passenger side of the Cherokee, near the fender-well and also on the low-side line. Its inlet pipe is the section of the low-side line that goes into it from the evaporator, behind the dash. A thermometer may be placed in the center duct of the vehicle to measure air temperature. A fully charged system should cool to about 40 degrees Fahrenheit or generally 30 to 50 degrees cooler than the ambient air, depending on the outside temperature and relative humidity. Some charging kits also come with a low-pressure gauge attached that can be used to determine when the system is fully charged.
Repeat the process with an additional can, if necessary. Close the valve handle when the can is empty, and disconnect from the low-pressure port. Replace the protective cap on the port, and save the charging kit for future use.
Items you will need
R134a charging kit
2 cans R134a (at least one containing red dye)
Jumper wire with alligator clips