R 134 or R 12

[lou-q]

I'm restoring our 67 convertible and the shop asked me if they should use 134 for the A/C. Should it stay R12 or should we change it to 134. I have a tank of R12 that is full.
Thanks,
Lou

[walt chomosh #23510]

Lou,
  I've tried R134,freeze12,and R414b in my 1955CDV before switching back to R12. The question I have for you is why  (since you have a tank of R112) wouldn't you put R12 in your Cadillac?.....walt...tulsa,ok

[scotth3886]

I'm restoring our 67 convertible and the shop asked me if they should use 134 for the A/C. Should it stay R12 or should we change it to 134. I have a tank of R12 that is full.
Thanks,
Lou

I converted back to R12 a few months ago in my 66 feetwood.  To get the full benefit, I have another issue that I have to take care of this spring with regards to the vacuum pot for the blend door.  It's the one on the driver's side of the heater box, which negates much of the gain at highway speed.  But sitting still the difference in outlet temp is considerable.  I have just to get the air flow coming out the dash vents instead of split between floor and dash.  With R12 I'm high 30s to low 40s with the car not moving, but in the mid 50s on a 95 degree day when at interstate speeds.  The R134 didn't get me below mid 50s sitting still and about 60 degree on the interstate was the best, which will never cool the car.

We've had a few cold days with no wet salt or salt dust on the roads so I've had it out to cars and coffee on some pretty cold Saturday mornings.  The auto temp control seems to work normally except for that blend door ducting in outside air. 

["Cadillac Kid" Greg Surfas 15364]

Lou,
You are down in Florida.  Some of the most extreme weather your '67 system was designed to handle.  At BEST switching to R-134a results in a 20% drop in capacity.  You make the choice.  This forum has seem this top[ic countless times over the last several years and if you do a search you will get a lot more answers.  You have R-12. Use it.
Greg Surfas

[79 Eldorado]

It's really scary to see anyone write "I reverted back to R12" at least without qualifying what was done.

The reason is if PAG oil was used for the R134a you will NEVER get all of it out of the system and R12 + PAG = ACID which will destroy the system. Even a small amount cannot be tolerated. It's not the same as when you move from R12 to R134a because when you do that the R12 is evacuated and it's a gas at basically any normal temp at atmospheric pressure. So R12 and PAG are never mixed going from R12 to R134a if the system is properly evacuated. The reverse is not true.

The only exception may be if ester oil was used for the R134a conversion. I didn't have much knowledge on ester oil but in a similar thread it was mentioned ester oil can be used for both R12 and R134a.

For R134a you should look into having better condensing. If you do you will be able to recover the performance loss and get back to the level of performance you had with the old condenser and R12. You also need to change the TXV or orifice tube to be sized properly for each.

Scott

[scotth3886]

It's really scary to see anyone write "I reverted back to R12" at least without qualifying what was done.

The reason is if PAG oil was used for the R134a you will NEVER get all of it out of the system and R12 + PAG = ACID which will destroy the system. Even a small amount cannot be tolerated. It's not the same as when you move from R12 to R134a because when you do that the R12 is evacuated and it's a gas at basically any normal temp at atmospheric pressure. So R12 and PAG are never mixed going from R12 to R134a if the system is properly evacuated. The reverse is not true.

The only exception may be if ester oil was used for the R134a conversion. I didn't have much knowledge on ester oil but in a similar thread it was mentioned ester oil can be used for both R12 and R134a.

For R134a you should look into having better condensing. If you do you will be able to recover the performance loss and get back to the level of performance you had with the old condenser and R12. You also need to change the TXV or orifice tube to be sized properly for each.

Scott

Scott, Scott here.  Ester.  The selling dealer in Scottsdale wouldn't tell me who worked on it.  They sent me the last service receipt, but with the provider's name cut out with scissors.  Ok, that was plenty chickenchit.  What they forgot was the last oil change sticker up in the blue tint band of the windshield.  Sure enough, that was the guy.  He strongly recommended against changing to 134 in the Scottsdale / Phoenix area so he figured they'd be back to convert back so he used ester.  Plus if I ever had to change and update, no complaints, as everything is original and somehow not leaking.  The only issue is the vacuum pan for the blend door that I got to get in there one of these days and replace.  It's shot as I can't pull a vacuum on it.  If I could have had all the air flow from the dash vents instead of half vents and half floor, I could have probably lived with the 134. 

[79 Eldorado]

Hi Scott,
Ok I think I follow you so when they originally converted to R134a he verified they used ester... if true you should be fine as I understand. Good you were able to do the detective work

Scott

[lou-q]

Hi,
Thanks for all the replies. The car is at our farm in Indiana. We use it up there on all the beautiful roads through the Hoosier National Forest. My next door neighbor knew about us having old cars and was the one who handed me down a tank of R12.
It's never had 134 and I will keep it that way.
Thanks again for the good info.
Lou

[76eldo]

Use the R-12.
It will give you much colder air at the vents.

[scotth3886]

Hi,
Thanks for all the replies. The car is at our farm in Indiana. We use it up there on all the beautiful roads through the Hoosier National Forest. My next door neighbor new about us having old cars and was the one who handed me down a tank of R12.
It's never had 134 and I will keep it that way.
Thanks again for the good info.
Lou

I have a partial tank that I've had for decades that's prolly 80% full and a bunch of 12 or 14 oz cans.  If the system isn't leaking then there's little environmental hazard to using R12.  I topped off my 63 GP last summer that hadn't been charged or touched in 21 years.  It needed maybe a 1/2 pound.

[The Tassie Devil(le)]

The authorities aren't concerned about what is being retained within the systems, but when the stuff escapes, as a direct result of a fractured line, or other damage during a crash.   Thereby uncontrolled releasing of an illegal substance into the atmosphere.

Bruce.

[fishnjim]

R-12 can still be used - "legally".   It's still made, too.   Most of the 12 was banned for foam applications.   I made replacement blends with 12 in it for HFCs, too.   Crazy situation refrigerants.   They just stir the pot to raise the price.   Legislators don't know what they're doing, frankly...    It's been a roller coaster for decades "saving" the planet???
The current genius US "virus relief" bill has verbage to curtail HFC manufacture*, so R143a is again, going out.   But it's been that way for two decades now.   That's how a few lines of extend unemployment and send checks, gets to 1200 pages and takes months of politicization to get out the door.   It's more case of ideology than environment.   People believe what they want to believe and act accordingly, creating mythology.
* - exactly what does that have to do with the virus?   

["Cadillac Kid" Greg Surfas 15364]

This topic seems to always bring some of the urban myths out of the closet and generate new ones.
R-12 IS NOT being manufactured, but since it must be recaptured from old systems such as refrigerators and commercial refrigeration before they are destroyed there is a more than adequate supply of reclaimed and recycled R-12.  Just bought a 30# drum for the bargain price of just over $1200.00.
The original rational for eliminating R-12 was to prevent the destruction of the Ozone layer which R-12 and other Chlorine based chemicals did.  The major culprit was the foam blowing industry, but automotive AC got caught in the same net.
Laws were enacted to prevent the uncontrolled release of R-12, and systems choosing to use it had to be "tightened up".  Fines of many thousands of dollars could be imposed for its intentional release, NOT AN AUTOMOBILE ACCIDENT WHICH WAS NOT INTENTIONAL.
Enter R-134a.  This was used as a replacement for R-12 and required the components of all systems using it to be designed specifically for this refrigerant.  It was never intended as a drop in for R-12.

Now just in passing I will mention this "changing of the guard" in refrigerants was not started with the change from R-12.  Originally the most common commercial refrigerant was Ammonia.  Fantastic refrigerant but a bit nasty on humans. A leak was not a pleasant event.  Then for residential and commercial refrigeration Sulfur di-oxide was used followed by Methyl Chloride.  Again two excellent refrigerants but quite nasty for living things.  R-12 was invented in the 30's and was used almost exclusively for some 60 years.  Then the world and science changed.
Global climate change entered the picture.  Whether you believe in climate change or not the fact that the CO-2 level in the atmosphere was increasing dramatically and THAT again is a hazard to all animal life although plants love it. R-134a was determined to increase the level of CO-2 by its production and its release into the atmosphere, so a search began for its replacement.
At this point two things happened. Germany developed a (semi) viable system using , of all things CO-2 as the refrigerant, and the EU jumped on it by setting a deadline (I think it was about the year 2000) for the sale in the EU of automobiles using R-134a.  This cut out any cars not using the patented CO-2 system for which the manufacturers would have to pay the patent holder a royalty.
Enter (again) Du-pont.  They developed a new refrigerant HFO-1234yf, that met the criteria for CO-2 and you may have noticed that all Cadillacs and other American cars with AC manufactured after about 2010 use this as a refrigerant.
Things change. The world changes and so do refrigerants. 
Perhaps I am naive, but I see no great plot against the owners of old Cadillacs to make their life miserable.
In the words of Don Amechie "tings change" 
Greg Surfas

[TJ Hopland]

30# for $1200 seems like a big number but some quick math,  roughly 3# per car so roughly 10 cars worth so only $120 per car.   Sure its more than it would have cost you to pick up a can at your local parts store in 1975 but 45 years later it doesn't seem like a bad deal.    You are going to be paying at least another $120 for labor assuming nothing is actually wrong with your system.     $300 for working AC would seem like a deal to me,  seems any time I have an AC problem its $850. 

["Cadillac Kid" Greg Surfas 15364]

TJ
I still have a case (12 cans) of R-12 I bought for 69 cents a can decades ago.  For some reason I find it hard to use them.
As far as costs are concerned I use the example of how much we will pay for some object made of Unobtanium that we will buy for several hundreds of dollars for our cars and never think about it as being exorbitant 
Greg Surfas

[79 Eldorado]

The term normally associated with the CO2 issue Greg mentioned is "GWP" or Global Warming Potential. So while R134a does not deplete the ozone layer, it has a high GWP value; the lower the better.

The issue with CO2 which the German OEMs were moving towards is that the operating pressures are insanely high. That means it would never work in an existing system. The high pressure also makes the system difficult to seal at the mechanical connections between components.

One other comment. Someone wrote if the system doesn't leak there isn't an issue with R12. There's a saying in leak testing: Everything leaks; it's just a matter of how much. That statement is true. To be fair though the leak rate can be managed to the point which a system essentially does not leak. The standard, in terms of refrigerant and cars, is in the neighborhood of 1lb in 20 to 40 years to put it in perspective. The real issue with R12 is it contains chlorine which acts like a catalyst for breaking down Ozone. The science of the term, we hear a lot in terms of an automotive component, is that it's a substance which can cause a change without a change to itself. In this case it boils down to a small amount of chlorine can destroy a lot of ozone.

Propane is also an excellent refrigerant. Of course it's flammable but if propane was used as a replacement for R12 or R134a the total weight of propane is much less (around half). So it's flammable, like other things in our cars, but there is very little total mass if it were to be used. It is even being used in Canada as a replacement for both R12 and R134a. I guess if gasoline was never used in a vehicle we could never introduce it now.

Scott

[scotth3886]

The term normally associated with the CO2 issue Greg mentioned is "GWP" or Global Warming Potential. So while R134a does not deplete the ozone layer, it has a high GWP value; the lower the better.

The issue with CO2 which the German OEMs were moving towards is that the operating pressures are insanely high. That means it would never work in an existing system. The high pressure also makes the system difficult to seal at the mechanical connections between components.

One other comment. Someone wrote if the system doesn't leak there isn't an issue with R12. There's a saying in leak testing: Everything leaks; it's just a matter of how much. That statement is true. To be fair though the leak rate can be managed to the point which a system essentially does not leak. The standard, in terms of refrigerant and cars, is in the neighborhood of 1lb in 20 to 40 years to put it in perspective. The real issue with R12 is it contains chlorine which acts like a catalyst for breaking down Ozone. The science of the term, we hear a lot in terms of an automotive component, is that it's a substance which can cause a change without a change to itself. In this case it boils down to a small amount of chlorine can destroy a lot of ozone.

Propane is also an excellent refrigerant. Of course it's flammable but if propane was used as a replacement for R12 or R134a the total weight of propane is much less (around half). So it's flammable, like other things in our cars, but there is very little total mass if it were to be used. It is even being used in Canada as a replacement for both R12 and R134a. I guess if gasoline was never used in a vehicle we could never introduce it now.

Scott

"1lb in 20 to 40 years to put it in perspective"

That sounds about right.  I added 1/2 lb to my 63 GP, a car I restored 21 years ago. 

[2manycars]

The entire climate control heat and AC on my 64 has been rebuilt, from the ground up. Only the vacuum parts weren't touched, since that is all good. I am sticking with R12. I am still working on the car - I just got the engine back from rebuild. Once I have the firewall repainted, the climate control will be reassembled and reinstalled. Everything is still capped and sealed from the rebuilder. The compressor already has oil in it. Somewhere, it is noted what it was filled with after the overhaul - probably the oil that is compatible with both refrigerants.

["Cadillac Kid" Greg Surfas 15364]

Bill,
I would be real careful myself regarding the oil in the compressor.   Rebuilders typically only leave an ounce or two in the compressor.  Anytime I replace a compressor, regardless of where it came from (unless I have done it myself) I drain the oil (drain plug in the "belly" of the compressor) and refill it with the requisite 5-1/2 ounces of oil. Take no shortcuts and refill the system in the quantities and the locations the factory service manual suggests.
Greg Surfas