How to Retrofit Air Conditioning in Cars to New Refrigerant

If A/C in your car no longer works, you can retrofit your air conditioning system to accept refrigerant currently available. Before you do this, make sure your A/C tries to turn on (clicks and runs, but does not get cold).

1. Skip to step 4 if your car is a '96 model or newer, If your car is a '95 model or older, continue reading. Many GM models from '94 on are R134a and would fall under the '96 and newer category. To verify, look under the hood of the car for a label that will tell you what refrigerant the system uses.
2. Have the freon (R12) still in the system evacuated with a recovery machine by a licensed professional.
3. Buy a "dryer" at an auto parts store, and replace the original in your car. A sales rep in the store can tell you where the dryer is and how to change it out.
4. Replace the dryer. Remember to replace the "o" rings supplied with the new dryer.
5. Go to your nearest auto service center and ask them to vacuum down your A/C system (at a cost of approximately $5-15). This process removes atmosphere from the system.
6. On existing R-12 systems you might want to consider a replacement refrigerant -- next step or if not, Purchase an A/C retrofit kit for R-134a refrigerant ($30) at your local auto parts store. Also purchase enough refrigerant to fill your system (the sales rep can tell you how much you need). Do not forget to buy a can of "oil charge" for your A/C system. Failure to do so will seize your compressor, necessitating a $500+ repair.
7. Explore using a substitute for R-12 systems. There are other refrigerants available that are superior to R-134 for use in older R-12 systems and may also be used in R-134 systems. In general, they are cheaper than R-134. However, be aware that some of these are based on flammable gases. Since your fuel system is also pressurized, that would be an equivalent or worse fire hazard. There are several EPA accepted R-12 replacements, check with the EPA web site for specific approved products (Freeze 12 is a good one.)
8. Connect the kit to your car, referring to the supplied instructions.
9. Start the car and turn the A/C on full blast. Use the kit to add the oil charge first, and then the refrigerant that your car needs. Be careful not to overfill. Note: To get the refrigerant to move from the can into the system, you can use a pitcher of warm water. Put the can right side up into the water and stir the water with it. The temperature difference will help force the freon into the system.
10. Keep the car running, and check to see if it produces nice cold air. If it's not really cold, you need to add more refrigerant. It is highly recommended to use gauges to monitor the pressure on your AC system. If you don't, you may blow a seal costing lots of money to fix!
11. For more details on the above procedure check out this site: http://www.aa1car.com/library/ac_recharging

NOTES

• It is illegal and harmful to the environment to release refrigerant into the air.
• DO NOT forget to get your A/C system evacuated prior to adding new refrigerant. R-12 refrigerant (freon) DOES NOT MIX with R-134a refrigerant (the new stuff). Failure to do so will cause the "black death syndrome" in which the conflicting refrigerants will turn into a black goo that clogs your entire A/C system, resulting in a $900 plus repair.
• DO NOT FORGET to REPLACE YOUR DRYER in cars '95 model year and older. Failure to do so will result in the "black death syndrome" as well.
• Follow instructions that come with your retrofit kit and you will be fine.