76 Regency

Hey gang. Anybody familiar with R12a? My buddy is a BMW master tech and foreman and just told me about this. He said it's more efficient and colder than R12 and R134 and also charges without needing the system to have a vacuum on it. It almost sounds too good to be true but he's done his homework and has been hearing a lot of good things about it. Hoping this could be a great new product that could make getting older a/c systems running cold well fairly easily. Hoping to hear some more positive feedback on this.ft

jensenracing77

If it is the same thing I looked into a couple years ago it is not worth it. There are a couple so called "drop in" refrigerants that claim to work in an R12 system but most of them have higher head pressure and have a large percentage of propane in them. It would be best to stay with R12 or convert to 134A. As far as evacuating the system, ALL refrigerants will require the system to be evacuated (vacuum pulled). The vacuum is about pulling non condensables out of the system. Not much to do with the refrigerant itself other than not mixing it with the non condensables.

Your guy may be talking about adding this R12a to a low system with R12 and that would not require an evacuation but it is also illegal to knowingly mix refrigerants.

1970-W30

Go to www.duracool.com lots of info there, I've been running it for a few months, the R12a actually has lower high side head pressure (around 150psi) then 134 or R12.

Junkman

If it is so great, why haven't the automobile manufacturers adopted its use in their new cars, and why haven't the air conditioner manufactures recommending it for use in both residential and commercial use? I am very suspicious of manufacturers self serving claims of compatibility etc.


Here is a good article for educational purposes.


From the EPA... Unacceptable Substitute Refrigerants Duracool is at the top of the list!
The interesting thing is that from what I was told, the EPA doesn't have the power to stop the sale of these "refrigerants" and I don't know why.

Olds64

John, here is another thread on r12a that I just resurrected:

https://classicoldsmobile.com/forums...ot-r12a-2.html

It has a lot of good info. FWIW, I'm still not convinced that the drawbacks of r12a outweigh the cost of r12. For me, I plan on doing all of the work myself. The only thing I might have to get an AC shop to do is pull a vacuum on my system. They do sell vacuum pumps at Harbor Freight though... last major purchase I made at HF was a chain s... or I mean lemon.

Fun71

Years ago I bought a very nice used RobinAir vacuum pump from an online pawn shop for a fraction of the new price. Even with that purchase price and the purchase of a flush gun, solvent, and spring-lock tools I was able to replace the compressor, accumulator, high pressure line / orifice tube on my wife's car and recharge the AC for a lot less than I would have paid a shop to do the work.

Junkman

You can pull a vacuum, and it can hold the vacuum, however, when you charge the system, it might not hold pressure. When the cost of refrigerant went up, I invested in a tank and fittings to charge the systems with nitrogen after I pulled the vacuum. I found that sometimes, a fitting will hold a vacuum, but won't hold pressure. That nitrogen system has saved me from filling a system that would eventually leak under pressure. Having the proper tools to do the job properly isn't cheap, however, it is a lot less expensive than having to do the job a second time for free.

1970-W30

I'm not sure why "Junkman" resurrected a 4 year old thread, but I'm pretty sure the OP
has made up his mind on this years ago on this subject............

Junkman

I was doing a search and found this old thread, and it is my belief, that when you find information that might be misleading, that commenting on it, is the best method to keep the flow of knowledge. Many times, people just search for information, and accept on face value what has been posted, even if it isn't correct, or could cause them problems later on if they use this old advise. At some point in time, use "old timers" will be gone, and hopefully, our advise will continue to be of value to those that are starting up in this hobby. I know that a lot of what I have learned came from "old timers", when I was young. I worked on many of the cars when they were new, and today, you and others are working on them doing restorations. My first restoration was on a 5 year old 1955 Chevrolet BelAir convertible, and back then, you could buy all the NOS parts you needed at the local dealerships for next to nothing, since NOS had little to no value to them.

Mike77

How does a sealed system hold vacuum but not hold pressure? I been a commercial A/C technician for 40 years and I have never seen that. I would sure be interested in learning something new.
Mike

Koda

I can give a specific, violent, example. A bunch of years ago, we had a trial Sequoia on the Indiana plant's west line. It was missing a bolt holding the hose to the condenser because it was a parts test scrap car. The vacuum held because it was sucking the line into the fitting. The pressure did not hold because the bolt was gone and it blew it off.

bw1339

I used to make pressure switches. Elastomers can often seal when the pressure gradient is in one direction, but leak when the direction reverses.

Olds64

FWIW, I bought a 12a recharge kit to convert the AC on my truck. I will let everyone know how it works.

jensenracing77

Mine is most often the reverse. I regularly have systems that will hold pressure but not a vacuum. I do have O rings from time to time that will be like above but not often. Our systems are much higher capacity with lots more valves than an A/C system. It is amazing what can happen when some of these valves stick or get installd wrong from the factory. We have between 14 and 30 lbs of refrigerant in these refer units.

Mike77

Interesting experiences from a different perspective. I usually do service/repair. My approach is different, I usually repair, leak test, then vacuum. I could see how 2 machined surfaces would seal in a vacuum application without pressure testing first. Some of the large equipment I service have hundreds of pounds of refrigerant.
Thanks for the replies
Mike

Olds64

I charged my truck with r12a. It works great! Definitely worth the $65 I spent.

Let me expand a little.

I installed the r12a without evacuating the system. I used a r134a hose with a dummy gauge to install it. It had been sitting in my garage for years from when I added r134a to my wife's VW. Unfortunately, the hose was cracked and I lost half a can before I caught it and changed to the hose included in the kit. That being said, it still performs better than a r134a conversion.

Eventually, I may evacuate the system, replace the drier and hoses and recharge it with r12a. Especially if I look at doing head gaskets and a turbo. However, if it lasts at least a year I will be happy.

Apparently, the leak wasn't so bad that it lost pressure overnight. I drove the truck at lunch time and it was still working great. The first 1/2 can I installed was r12a with stop leak.

Ultimately, I am convinced. I will never be concerned with sourcing r12 again since r12a is available. If they completely ban it then there's always r152.