Adding R-12 to a system is easy if you have the R-12 cans and the tools, but they are very uncommon now. R-12 was also getting very expensive, but I have heard that demand is so low that prices have dropped down again.

I think you need an EPA permit to buy R-12 yourself in a large container, and the small do-it-yourself cans have not been sold for several years. It will also be hard to find someone who has it on hand anymore in their shop. The size of the fill port fittings is also different than R-134a, so you need hoses that are specifically for R-12.

There are some R-12 substitutes that you might try, if you are convinced it just needs a top off. You will still need the right charge hoses, and you should have gauges so you can verify what the system is doing. The only other quick home fix is a cheap R-134a conversion kit. Some folks have had good luck with them, but most don't work very well. The best choice would be an R-134a conversion by an AC shop.

Bruce

 

Hi
The guy who told you it was 2 can's short, was he guessing or did he put a set of gauges on & check it. Anyway, I see r12 frequently on Craigs list. If it was checked with gauges, then you only need one line to fill it. you fill on the low side (the cold line, I'm assuming your vehicle is an 80s something GM the cold line going to the receiver/dryer. Has this car been sitting or did the air just start cooling less & less until there was no chilled air coming from the vents?
Rich

 

if done right no problem . if done wrong you loose several fingers . leave it alone and have it done by a professional . if it is low you have a leak anyway. time to switch it over to 134 .

 

Hello friendly forum! My car has the old-school R-12 style air conditioning system. I had my mechanic look at it today and he said it was "about 2 cans short". I asked him if he would recharge it but he says they don't do the old R-12 systems and doesn't know anyone who will! So I'm wondering: is this an easy job that I can do myself? There is a schrader-valve-looking valve right on the AC pipe right next to the radiator. Do I just hook up something to that valve and pump the fluid in there or what? Has anyone done this to their car here on the forums? Thanks for the tips,

Rockworthy

Find an AC shop who has or can get R 12. If you cant, then go to the exspense of switching to R 134 a .
Stay away from those R 12 Drop ins or "equivalents" , once you put that in shops consider your vehicle contaminated and many will turn you away. Also some of those are very dangerous as they contain Hexanes and all kinds of scary stuff.
As mentioned do it right, dont take the easy way out, it will cost more than you think.

 

I was going to wait for the OP to reply.
The reason I put that down is I feel as if he's going to get the R12 from someone somewhere. He's been checking it out, he has asked about the Schrader valve. Next he'd be asking a friend & the friend may know less the him, so rather then let him go & try charging the system on his own. I thought it good to tell him what line to put the stuff in so he wouldn't try charging through the high side. Also the questions I asked were to find out how the system became low. I would have gotten around to explaining how to switch over to 134 correctly.
Rich
PS I think the shop he went to doesn't have R12 licensing. that's why he was told "they don't do the old R-12 systems"

 

Yeah, at this point I would recommend he take it in for an R 134 a conversion. Not terribly exspensive, especially if you price R 12 vs. R134 a

The first time you need to refill the system because it sprung a leak you will save money on the price of refrigerant alone.
Lots of myths about R 134 a out there. Its pretty aggravating to say the least.
I do conversions and I have great results, just gotta follow the guidelines.
Old systems cant perform as well as systems that were designed specifically for 134 a , but you can get duct temps that are still very acceptable and totaly capable of keeping any car comfortable in the heat of summer.

 

Convert to 134A

Yeah, at this point I would recommend he take it in for an R 134 a conversion. Not terribly exspensive, especially if you price R 12 vs. R134 a

The first time you need to refill the system because it sprung a leak you will save money on the price of refrigerant alone.
Lots of myths about R 134 a out there. Its pretty aggravating to say the least.
I do conversions and I have great results, just gotta follow the guidelines.
Old systems cant perform as well as systems that were designed specifically for 134 a , but you can get duct temps that are still very acceptable and totaly capable of keeping any car comfortable in the heat of summer.

Latech nailed it. I spent 20 years on the industrial /commercial side of the industry, and we saw the same thing. Typically you see anywhere from a 10% to 20% reduction in efficiency with the existing condenser. Still better than dealing with the R-12. But, you do need to follow the instructions! Probably the most important aspect would be making sure you get ALL of the old oil out. R-12 used mineral oil, R134A typically uses POE, which will not mix with the mineral oil, and the old mineral oil is not miscible in the 134-A. Meaning that the oil will not be transported around the system properly. It causes other problems as well, but the oil issue is the biggest.

 

Use HC12 or Dura Cool.
Better performance, cheaper
compatible with everything, all oils everything