1970s 1975 R22 refrigerant??

[Richf1966]

Can someone tell me what the correct refrigerant is in 1975 Eldorado? I have the 75' Cadillac shop manual supplement and they refer to the refrigerant as R-22 in several places. I have never heard of this, but I do not see any other threads addressing this information. They explain that in 75 "the expansion valve has been upgraded and modified from VIR assembly now designated as EEVIR is incorporated on all cars." on page 1–10 in explanation of the expansion valve it refers to R-22 on more than one occasion. On page 1–13 it again refers to R-22 when discussing the EEVIR function. I've included an excerpt that shows exactly what I am speaking of. Can someone please explain this to me. Thanks!

[jwwseville60]

All American cars before 1991 used R12 as far as I know. R22 is a variant that was supposed to be less harmful to the atmosphere. It was used primarily in home systems.

You can use a newer refrigerant R12 replacement or convert to R134A, but it will only be 70% as cold as the original. I know this because Ive tested the vent temp on my 1960 which is original stock R12, and then on my 1963 which has the Old Air R134 compressor. A 7 deg. difference is big.

There are VERY few shops that have an old R12 recovery system and most wont deal with it due to strict laws.

https://www.hvac.com/expert-advice/r22-refrigerant/

"First of all R12 is the "older version" of freon that is no longer used. Also, it was used primarily in car air conditioning."

"As for R22, it is part of the new family of freon that supposedly hurts the ozone layer less than the ones before it (hence the reason why it was banned). R22 is one of the replacements for R12."

[TJ Hopland]

I will be curious to hear what Greg has to say about this.  It seems like R-22 appears too many places in the manual to just be a typo so at some point it seems like they were at least considering it.  Anyone else got a 75 manual to see if it says that in apparently all the copies of the manuals or if it was just some?

["Cadillac Kid" Greg Surfas 15364]

Rich,
What they are talking about  with R-22 is the minuscule charge in the expansion valve capsule in your VIR. NOT THE CHARGE IN THE REFRIGERATION SYSTEM ITSELF. R-12 is the refrigerant intended for use in your system, and although it has become pricey it is still available.
R-22 was used in domestic and commercial air conditioning which operated at substantially higher pressures. As opposed to 32/220 psig low and high pressures in your R-12 system, 60/350 might be the equivalent operating temperatures in a commercial AC system.
Greg Surfas

["Cadillac Kid" Greg Surfas 15364]

I was typing while you were posting TJ

["Cadillac Kid" Greg Surfas 15364]

By the way, just about any refrigerant or mixture of refrigerant can be used in the diaphragm portion of an expansion valve or TX capsule. The pressure of the refrigerant is determined by the temperature of the return gas/liquid refrigerant mix and an opposing spring is used to operate a needle valve that controls the refrigerant flow through the valve itself.
Greg Surfas

[TJ Hopland]

I knew Greg would have the answer.  Was that capsule serviceable or are they just explaining how the VIR works?  Is the capsule a common failure point in the VIR?   

I was also curious and now also have the answer to what was really different about R-22.

I assume if they wanted to they could have used R-22 in cars?  It just would have meant literally heavier (to handle the higher pressures) and likely more expensive components for no real gain in performance or efficiency?   

["Cadillac Kid" Greg Surfas 15364]

In the VIRs and EEVIRs both the (they still called it) POA and the TXV "capsules" are replaceable. The "POA" capsule was severely simplified to just a sliding sleeve valve and spring which was prone to getting gummed up if there were any contaminants in the system. The basic VIR/EEVIR concept was prone to poor performance since they were extremely charge dependent and the site lass in the VIR shows clear when the system is still over a pound sort of refrigerant.
As far as R-22, the critical temperature of 205 degrees F. means that when over 205 degrees, a temperature commonly experienced in automotive underhood conditions, the refrigerant will not condense, regardless of the pressure. Not a good thing.
Greg Surfas

[dplotkin]

All American cars before 1991 used R12 as far as I know. R22 is a variant that was supposed to be less harmful to the atmosphere. It was used primarily in home systems.

You can use a newer refrigerant R12 replacement or convert to R134A, but it will only be 70% as cold as the original. I know this because Ive tested the vent temp on my 1960 which is original stock R12, and then on my 1963 which has the Old Air R134 compressor. A 7 deg. difference is big.

There are VERY few shops that have an old R12 recovery system and most wont deal with it due to strict laws.

https://www.hvac.com/expert-advice/r22-refrigerant/

"First of all R12 is the "older version" of freon that is no longer used. Also, it was used primarily in car air conditioning."

"As for R22, it is part of the new family of freon that supposedly hurts the ozone layer less than the ones before it (hence the reason why it was banned). R22 is one of the replacements for R12."

Not entirely accurate. R22 was never used in automobiles, only stationary AC systems. R134 can replace R12 in an R12 system and work as well, I repeat, as well as R12. The STV or POA valve can be recalibrated for R134, but I run R134 in a 62 Bonneville (same as Cadillac system) and it cools to 42 degrees, as cold as you want it without freezing the evaporator. I have 134 in a 68 Chrysler, same thing, any colder would be too cold.

A 7 degree performance difference informs me that you have overcharged, undercharged or have some other deficiency in your system. I have 12 years of proof that R134 works beautifully in a 62 steel condenser STV GM system.

Dan

[jwwseville60]

Sorry, but I fervently disagree.
I have fixed 4 AC systems in old caddies. Both gasses.
The high pressure R134 does NOT cool as efficiently as the low pressure R12 in a 1950s-1970s car.
If you replace every part in the system with R134 specific parts them maybe so, but modern cars have much higher fan speeds than old ones to make up for the lower specific cooling.

Humid states are not the same as western drier ones. You will see a big difference regardless of vent temperature.

R12:  34 deg at vent

R134:  42 deg at vent

[Eric DeVirgilis CLC# 8621]

Agreed with John. R134A will not cool as well in a system designed for R12. You will discover this when you take your 134A converted system out when the temperatures are in the 90s or higher, just when you need every drop of cooling efficiency the system can provide.

["Cadillac Kid" Greg Surfas 15364]

If the powers that be confirm that I'll be doing an AC seminar at the Gettysburg GN next year perhaps it might be worthwhile to spend a little more time on the use of alternate refrigerants as well as the projected availability of refrigerants in the future.
Greg Surfas

[Richf1966]

Thanks for all the input and information. Greg, can you send me a pm to a source as I am not having any luck here in SW Florida.

[scotth3886]

Sorry, but I fervently disagree.
I have fixed 4 AC systems in old caddies. Both gasses.
The high pressure R134 does NOT cool as efficiently as the low pressure R12 in a 1950s-1970s car.
If you replace every part in the system with R134 specific parts them maybe so, but modern cars have much higher fan speeds than old ones to make up for the lower specific cooling.

Humid states are not the same as western drier ones. You will see a big difference regardless of vent temperature.

R12:  34 deg at vent

R134:  42 deg at vent

https://photos.app.goo.gl/jdmPMQbv8h8RAK4T8

[dplotkin]

Sorry, but I fervently disagree....

You need not apologize or be fervent. Your experience is at odds with my 25 years experience with 9 60's Chrysler, GM and Ford systems using both gases. Your experience differs from mine and many others I know. We can agree on that.

If on the other hand you are a PME, you have my attention.

I don't advocate for a gas either, I run 3 on R12 the rest 134 all perform equally. Again, my experience. 

Dan

["Cadillac Kid" Greg Surfas 15364]

ALL refrigeration systems be it mobile (auto AC) , commercial or residential work best with the refrigerant the equipment was designed to use. Many of them can and sometimes do operte using alternate (to the original) refrigerants and the results can be good or bad, depending upon a myriad of other details in the set up and operation.
Greg Surfas P.E.

[Pghcc2006]

Hey Greg, while you're here, what do you think of this old post on a C3 Vette forum in regards to modifying the VIR to work with R-134? I've never seen this anywhere else and post is almost 20 years old.

https://www.corvetteforum.com/forums/c3-tech-performance/1146845-why-charging-with-r134a-on-a-vette-with-a-vir-a-c-system-is-not-the-best.html

[Eric DeVirgilis CLC# 8621]

You need not apologize or be fervent. Your experience is at odds with my 25 years experience with 9 60's Chrysler, GM and Ford systems using both gases. Your experience differs from mine and many others I know. We can agree on that.

If on the other hand you are a PME, you have my attention.

I don't advocate for a gas either, I run 3 on R12 the rest 134 all perform equally. Again, my experience. 

Dan

My experience comes from over 35 years in the car business and I've never found R134a conversions to perform equally by any stretch of the imagination, particularly in temperature extremes. Furthermore, R134a is far more prone to escaping from R12 systems due to the smaller molecule, necessitating more frequent recharges. If you want equal performance with R134a in an R12 system in all ways, you're looking at a multi-thousand dollar bill to do it right (like the one Greg did on a '66 convertible some years ago or something similar) not some slap-dash $100-$200 "conversion" done by the local corner garage.

[dplotkin]

Furthermore, R134a is far more prone to escaping from R12 systems due to the smaller molecule, necessitating more frequent recharges.

I appreciate that you qualified what you wrote by stating it is your experience rather than a categorical assertion.
We've heard since 1992 that a R12 system must have a multi-thousand dollar conversion to work as well. The aftermarket industry made a lot of money on O rings and hoses and who knows what else. It was BS then same as it is today. But still there are those who preach gospel that only R12 will work well.

I have a 1962 Bonneville, stock A6 STV system, original hoses on 134 for the last 8 years that today discharges 38 degree air at a 90 degree ambient and 65 degree dewpoints. The same is true of a 68 New Yorker, RV2, EPR in place and original hoses, same performance. The molecules are smaller yes. The hoses are not a problem - in my experience.

The Corvette Forum mentioned above is another good example. I am a member. Some of the most knowledgeable auto minds traffic on that forum where a great many have AC cars using 134. Read through those posts. You will learn that it is not just me, but many others who have a different experience than yours.

I don't mean to argue or pick a fight. I don't like opinions confused with irrefutable fact circulated where those without our knowledge and experience come to learn.

We can agree our experiences are not the same.

Dan

["Cadillac Kid" Greg Surfas 15364]

It seems like every time ANY aspect of automotive AC is discussed, the thread digresses to R-134a and its application in R-12 systems. This thread is no exception. The question was regarding R-22mentioned in the FSM.
For the most part, we are discussing cars near 50 years old and older which were designed for R-12. Switching to R-134a has been discussed to death for most of those 50 years. Yes/no, No/yes, yes/no.
Well folks all that will soon be just academic. Since 2021, R-134a has not been used in new production auto AC systems. The phase-out in the short term will mean a reduction by 2030 to only 20% of current production. The short version is the price is going to skyrocket to be equal or greater than that of recycled R-12.
Just think of all the newer car and light trucks made in the last 30+ years that will be affected.
That's my story and I'm sticking to it
Greg Surfas