How to Put R134a in a Nissan Questby Alibaster Smith
R134a refrigerant is used on many modern production vehicles as a refrigerant for the air conditioning system. Freon is no longer used as a refrigerant today, so if your air conditioning in your Nissan Quest starts to lose its cooling effect, you'll need to use the R134a. Vehicles manufactured after 1995 must use R134a and vehicles manufactured before 1995 must locate a mechanic that can recharge the system with R-12 refrigerant since it is no longer commercially available. If your Quest is a 1993 or 1994 model year, you cannot use the R134a refrigerant without taking it to a mechanic to have modifications made to your cooling system.
Connect the recharge hose that came with your kit to the R134a can of refrigerant. The end of the hose that connects to the can has a valve and a handle that controls the flow of refrigerant. Screw this end of the hose onto the top of the can.
Turn the valve handle clockwise until you hear the seal on the refrigerant break. You should hear a sudden hissing sound.
Turn the handle counterclockwise slowly to release a small amount of refrigerant into the hose.
Close the valve once a small amount of refrigerant is in the hose by turning the handle on the valve clockwise again.
Connect the other end of the hose to the low pressure side of the air conditioning service lines. The service lines are fairly thick metal lines running to the air conditioning compressor. They will run parallel to each other and should be located on the left side of the engine bay. The low pressure line will be indicated by a blue cap over the valve, while the high pressure line will be indicated by a red cap. Unscrew the low pressure cap by turning it counterclockwise. Screw the end of the hose into the low pressure side by turning the hose clockwise onto the valve.
Hold the can upright while you are filling the low pressure side of the A/C system. You do not want to introduce any liquid into the system. You only want to introduce the vapor from the can of refrigerant.
Turn on the Quest's engine and turn on the air conditioning. Set the A/C to the coldest setting and the fan speed to the highest setting.
Open the valve on the R143a refrigerant hose by turning the handle counterclockwise once again. The A/C compressor will start to draw refrigerant in from the can and charge the system. If your recharge kit came with a pressure gauge, note the pressure on the dial. When the pressure is between 25 and 40 PSI with the air conditioning running, the system is fully charged.
Close the valve on the recharge kit hose and turn the engine off. Remove the hose from the low pressure valve on the Nissan's air conditioning system and replace the low pressure indicator cap.
- Do not overcharge the air conditioning system. More is not better in this instance. Overcharging the system can negatively affect the cooling ability of your air conditioning system.