Home, Auto Repair Library, Auto Parts, Accessories, Tools, Manuals & Books, Car BLOG, Links, Index
If your air conditioner is not cooling well because the system is low on refrigerant, recharging the system with refrigerant should restore normal operation. This can usually be done with a few cans of refrigerant and a simple service hose connection.
First, wear safety glasses to protect your eyes. Also avoid skin contact with refrigerant. The chilling effect of spilled refrigerant can cause instant frostbite on bare skin or eyes!
Next, you need to figure out what type of refrigerant your vehicle requires:
On 1995 and newer passenger cars and light trucks up to about 2015, the correct refrigerant is R-134a. DO NOT use any other type of refrigerant in these vehicles. Refer to the A/C information decal under the hood to make sure your A/C system is a R-134a system.
Starting with model years 2014-2015 a growing number of vehicles now use a different type of refrigerant called R-1234yf. For these applications, use R-1234yf only, never R-134a.
-
On most 1994 and older passenger cars and light trucks, the original refrigerant was R-12. R-12 is no longer available to do-it-yourselfers (although some bootleg R-12 of questionable purity and quality is still coming into the U.S. from south of the border). When older vehicles with R-12 A/C systems need refrigerant, they can be refilled with recycled R-12 from other older cars (this requires taking your car to a repair shop for professional service), or with an alternative refrigerant other than R-12, or with R-134a (which requires certain modifications).
CAUTION: Mixing different types of refrigerants is NOT recommended. Use the same type of refrigerant that is already in the system unless you are converting an older R-12 system to R-134a or another refrigerant.
WARNING: Flammable refrigerants are illegal. DO NOT use any type of flammable refrigerant (propane, butane or flammable hydrocarbons).
For more information, see Flammable Refrigerants
Click here for more information about retrofitting older vehicles with R-12 A/C systems to R134a.
Next, you need to locate the service fittings on the A/C system. There are two: a LOW side fitting and a HIGH side fitting. The LOW side fitting is usually located on the suction hose or line that goes from the accumulator to the compressor. The HIGH side fitting is located on the line that goes from the compressor to the condenser.
On older R-12 systems, the LOW and HIGH pressure service fittings are screw-type schrader valves. On R-134a systems, the LOW and HIGH side service fittings are quick-connect style fittings. The LOW pressure fitting is SMALLER than the HIGH pressure fitting. Late model vehicles with R-1234yf also have unique service fittings that are different from R-134a or R-12 systems.
.. 
. .
High pressure gauge: When the reading gets up around 200 to 225 psi (R-12), or225 to 250 psi (R-134a), STOP. The system is fully charged and should be cooling normally. DO NOT add any more refrigerant.Remember to replace the plastic caps over the service fittings, and remove the jumper wire from the compressor if you had to jump it to make it run.
IF THE A/C SYSTEM STOPS BLOWING COLD AIR AFTER A FEW DAYS, WEEKS OR MONTHS
If your A/C stops blowing cold air several days, weeks or months after you recharged it, it means the system has a leak and the refrigerant is escaping. You should add some leak detection dye to the system to find the leak. The leak should then be repaired before the system is recharged again, otherwise you are just wasting your time recharging the system over and over again.
For entities selling or distributing refrigerants for use in motor vehicles, there will be new restrictions for R-134a and other substitute refrigerants sold after Jan. 1, 2018. The rule establishes certification requirements for buying large containers of refrigerant and mandates that small containers include a self-sealing valve.
Under the new requirements, anyone purchasing a substitute refrigerant for R-12 in a greater-than-two-pound container must provide the seller with evidence that the technician has a Section 609 Technician Certification. If the purchaser is not certified and is buying the refrigerant on behalf of a service facility, the seller must be presented with evidence that one or more technicians at the facility are certified.
Refrigerant wholesalers must retain an invoice listing the name of the purchaser, date of sale and quantity purchased. The wholesaler is not required to confirm any technician certification, but EPA is recommending that wholesalers obtain a statement certifying that the cylinders are to be resold to certified technicians.
Individuals do not need to have certification in order to purchase small cans (under two pounds) of R-134a. However, all cans produced after Jan. 1, must come equipped with a self-sealing valve capable of preventing the container from venting refrigerant after it is removed from the charging valves. Despite this new requirement, retailers are permitted to sell off their existing inventory of small cans that do not have the self-sealing valves, as long as they were purchased prior to Dec. 31, 2017.
Under former EPA rules, it was ILLEGAL for anyone (professional or DIY) to intentionally vent refrigerant from an A/C system into the air when servicing a vehicle. Professional repair shops are required to have refrigerant recovery machines. The machine must be hooked up to a vehicle BEFORE repairs are made to suck any residual refrigerant out of the system so that the vapors do not escape into the atmosphere when the A/C system is opened up to replace a component. The logic for doing this is to prevent older refrigerants such as R-12 that contain ozone depleting CFC compounds from getting into the atmosphere. It makes sense and is a good thing to do. But the EPA rules also applied to R-134a, which does not contain any CFCs and are not an ozone depleting threat. However, the rationale for also requiring R-134a to be recovered rather than vented is that it is a global warming gas, and therefore contributes to climate change. The EPA rules also require recovery of R-1234yf, but the rationale is less clear because R1234yf is neither an ozone depleting gas nor a global greenhouse gas.
Obviously a DIYer has no access to a refrigerant recovery machine so the issue of whether or not is acceptable to vent refrigerant when repairing an A/C system is moot. People just do it anyway. Besides, if your A/C system has a leak, chances are most or all of the refrigerant has already leaked out so there is nothing left to vent.
UPDATE: As of March 2020, the EPA has revised its venting and recovery rules.
The EPA published a new rule revising its previous rules that prohibited the venting of all refrigerants into the air when servicing a vehicle, whether or not they contain CFCs or global warming gases. R-12 still shout NOT be vented and should be recovered, but now apparently it is okay to vent R-134a and R1234yf during servicing procedures. No recovery is required.
The new rule also eliminates previous regulatory requirements regarding leak inspection and repair for R-134a and R-1234yf because both do not contain ozone depleting CFC chemicals.
.Click Here to view the latest EPA rules regarding venting of refrigerants.
The EPA also issued a proposed rule that would adopt three technical standards developed by the SAE International for A/C recovery and recycling equipment for R-1234yf. The new rule would require this equipment to meet the following updated SAE standards :
J2843 Recovery/recycling/Recharging Equipment for Flammable Refrigerants for Mobile Air-Conditioning Systems.”
J2851 “Recovery Equipment for Contaminated R-134a or R-1234yf Refrigerant from Mobile Air Conditioning Systems;”
J3030 “Automotive refrigerant Recovery/Recycling/Recharging Equipment Intended for use with Both R-1234yf and R-134a.
Air Conditioning Related Articles:
Click Here To See More Carley Automotive Technical Articles
Be sure to visit our other websites: