How To Add Freon To An Air Conditioning System

It is important to know how to add freon to an air conditioning system. This is because even though today’s cars are built to last, at around 100,000 miles their air conditioners begin to warm up. Fortunately, this is a problem that you can fix yourself.

To add freon to an air conditioning system, you will need:

  • An R-12 recharge kit
  • Some screwdrivers
  • A small set of box end wrenches
  • A can of UV dye
  • A UV light
  • A can of high-quality lubrication spray
  • A set of gauges for the R-12 refrigerant
  1. Inspect your air conditioning system. Listen to how the car's air conditioning system runs while your car is on. Put your AC on maximum fan and maximum cool so that you can check the air conditioner at this point too.
  2. Raise the hood of your car. Look at your car air conditioner compressor clutch. Listen for it to engage and disengage. If your refrigerant pressure is low, your clutch may not be operable. However, if you feel that the freon is at the proper level, you will want to test the pressure switch as well as your vehicle’s electrical connection to the compressor. You will know that the refrigerant is low if there are any bubbles or by looking at the sight glass on the receiver dryer.
  3. Make sure that the radiator and coolant, evaporator coil and belts are functioning properly. The compressor belts shouldn’t be worn and there shouldn’t be any cracks or frays. The condenser fan should be blowing air across the condenser coil. There shouldn’t be any oily residue or holes in the hoses. Bolts and brackets should be tight, and there shouldn’t be any oily residue, bends or excess dirt and debris in the AC condenser.
  4. After you are certain that every part of your car air conditioner is functioning properly, connect all gauges. Check the car air conditioner with the engine off to ensure that it is in the range of 125 PSI. If it reads below 125 PSI, you will need to add freon. However, if it is above 125 PSI, it is overcharged and will not cool properly.
  5. Start the car engine and let it run for a few minutes so that the system can stabilize. Check the gauges again. It should be between 20 to 30 PSI on the low side and 200 to 300 PSI on the high side. The pressure will rise at first as the clutch disengages. If there is very low pressure combined with very high pressure, then there is a blockage in either the orifice tube or expansion valve. You may need to replace one of these.
  6. To find a leak in your car air conditioner, you will need to use UV dye. Inject this into the low side and allow it to circulate throughout the system. Use a UV light to check for traces of the dye. If it only shows up on your compressor, the compressor will need replaced.
  7. Now it is time to add freon to a car air conditioner. In order to do this, screw the hose refill fitting onto your compressor fitting. Attach the refrigerant can to the puncture frame. Screw down the puncture fitting so the refrigerant can enter into the car air conditioner system. Once all the freon is in the system, unscrew the compressor’s fitting and start the car engine.

While it may sound easy to add freon to an air conditioning system, there are some warnings that you should heed for your own safety while doing this. Never lay gauges on your fender or radiator because these hoses could become tangled in your fan or belts. Remember that only a certified mechanic can add freon to a car that was made before 1993. Older vehicles need a different type of freon, which is difficult to find. Make sure that you know what you’re doing or a fitting could explode. This is also why you should always wear safety goggles. Don’t add too much freon as this can harm your car air conditioner system.

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