This is not an easy question for me to answer. Oh I can tell you the steps and procedures but the real question is do you have the required skill and tools to do it yourself properly. I generally do not recommend a DIY doing their own A/C work. The Federal Government has passed many laws governing the sale and use of refrigerants, specifically R12 and R-134a as used in motor vehicles.

Can I Recharge My A/C System Myself…?

The answer is yes, you can. However there are some problems to overcome first. The first of which is getting the proper refrigerant for your vehicle. In November 1992 a Federal Law was enacted stating that only “Certified” technicians can purchase R12 and R-134a refrigerants. To become certified you need to take, and pass, a written test as outlined by the Environmental Protection Agency (EPA). This is something all technicians must do before then can legally perform A/C maintenance and repair on your vehicle. The EPA laws and regulations concerning automotive refrigerants is know as “Section 608”

Why All The Laws…?

R-12 is an ozone-depleting chemical. I think we all know what it does and the effects it has on the Earth and the people who live there. Basically the law was enacted to keep people from adding R-12 to a leaking A/C system since it was often cheaper to add R-12 than to repair the leak. The EPA strictly regulates the sale and use of R-12. The manufacture of R-12 ceased on December 31, 1995 so now the only way to get R-12 is from someone who has stockpiled it or recovered from an existing R-12 A/C system. Needless to say the cost of R-12 has skyrocketed, costing as much as $100.00 per pound. I remember selling a 14-ounce can of R-12 off the shelf for only .99 cents. Up until 1994 you could only buy R-12 in bulk, typically a 30-pound cylinder. But the EPA has since closed that little loophole also.

As the supply of R-12 decreases and the cost increases many people will have to have their R-12 systems converted to use R-134a, which is “ozone safe”. Sometimes this will require replacing certain parts, A/C lines, compressor, etc… However, it is NOT illegal to own or use R-12, the law just makes it extremely difficult for you to get it.

Refrigerant Substitutes…

Since the increase of the price and scarcity of has risen, so too has the number of refrigerant substitutes. These are products that claim to be an exact, or better, replacement for R-12. I have even seen people who have put propane in their A/C systems!! Sure it’s a lot cheaper than R-12 but I think the cost of the funerals would be a lot more than what would be saved. It would be safer to drive a 1975 Ford Pinto backwards at 100 mph…

Before considering the use of a refrigerant substitute make sure the EPA approves it. However, this is in no way an indication of the quality of the product, just that it meets the requirements of being ozone safe.

Another problem is contamination of the shops A/C Recovery and Recycling (R&R;) equipment. It is required by Federal Law that all refrigerants that be recovered and recycled. If there is any other refrigerant than what the R&R; system is designed for it will contaminate the equipment and any refrigerant that has already been recovered.

Recharging The A/C System

Okay, so you have the refrigerant and all the tools you need to recharge your A/C.


Before we go on I must warn you that the A/C system works under high pressure and if you connect a can of refrigerant to the wrong fitting it can explode causing serious injury or death. Be sure to wear eye protection and avoid getting refrigerant on your bare skin. The refrigerant will instantly freeze the liquid in your eyes and will cause frostbite.

Okay, here we go!

  1. Locate the LOW pressure fitting of the system. If you can’t determine which it is, take it to a professional.
  2. Determine if you have an R-12 or R-134a system. There will be a decal that will tell you the type and amount of refrigerant your system uses. Most vehicles up to 1993 used R-12 and vehicles from 1994 and up use R-134a. R-12 and R-134a systems have different types of fittings so cross contamination would be idiot proof. However, when man makes something idiot proof, nature develops a better idiot.

CAUTION!! R-12 and R134a should not be mixed and are incompatible with each other. Use only the refrigerant your system was designed for.

<OL START=”3″>

  • Following the directions that came with your equipment, connect a can of refrigerant to your A/C gauges or recharging hose.
  • Open the valve for one second to purge the line of air and moisture. Your A/C system doesn’t like air and moisture and it will degrade A/C operation.
  • Now connect to the LOW side service fitting. It is most often located on the SUCTION side of the compressor or near the Receiver-Drier.
  • Hold the can upright so only vapor goes into the system. Holding the can upside down will allow liquid to enter the system and possibly damage the compressor. Likewise do not heat the can since this may cause the can to explode.
  • Now, start the engine and turn the A/C and blower speed on HIGH. Refrigerant vapor will begin to be pulled into the SUCTION side of the system. The compressor should be running or cycling ON and OFF. You may need to jump the Low Pressure Switch or run a fused jumper from the batter to the compressor clutch directly. This can take a while, about ten minutes or so, so be patient.
  • When the can is empty close the valve and disconnect the hose from the LOW side fitting. When taking the “empty” can off use extreme caution since there will be some refrigerant left in the can.
  • Go ahead and add additional cans to the system if needed until the proper amount is reached.

The most common mistake that is made is overcharging the system. Too much is just as bad, if not worse, than too little. The system needs the proper amount of refrigerant to operate at peak efficiency. Check the A/C decal to see how many ounces of refrigerant your system requires and put only that amount in. If the system is partially filled and there is no sight glass you will need to have it evacuated before recharging it or add no more than one or two cans. It is against Federal Law to vent any kind of refrigerant into the atmosphere so make sure it is R&R;’ed. If your system does have a sight glass add refrigerant until most of the bubbles are gone and the refrigerant runs clear.