vetter61

What is involved with converting A/C system from R12 to R 134

wmf62

back when 134a was first used, and people began to run out of R12, the 'naysayers' predicted doom and gloom and yelled "the sky is falling, the sky is falling"..

conventional 'wisdom' at the time dictated that all seals and hoses needed to be replaced; not true, eventually that was debunked as more 'sky is falling' BS...

i suggest that if you have to add refrigerant oil, that you use an 'ester' oil.
Bill

dplotkin

It was never conventional wisdom, but it was BS.

To play it safe you can change the oil out to 134 compatable but i know lots of fellows who don't even do that.

I've done it with a 62 Pontiac & a 68 Chrysler. Both steel condensers like your car. I changed the oil, sucked them down & charged to 3/4 the R-12 capacity with 134. Get 38 degrees from both for over 4 years now.

Knock yourself out...cold!

Dan

Stan's Customs

Do you have functioning R-12 system? If you do Freon is still available ..just replace eth O-rings at each joint and repair whatever is wrong with the system.

R-12 condensers are to small to work well with 134-A, unless you live in a moderate climate.

If you are used to a properly functioning r-12 system, you will never be satisfied with a 134-a retro fit.

...at least I have never been, and I've converted many of them back in the day. Never again...

But..I guess I'm spoiled...38 degree is possible with 134-a. 32 degree air is common with R-12. (...referring to systems that were originally charged with R-12).

Good luck Stan...

dplotkin

I must respectfully disagree with Stan:

1. R-12 condensers will work fine with 134 in most any circumstances where a hobby car will be used.

2. I have two cars that I retrofitted from 12 to 134 in which you can not tell the difference in cooling performance whatsoever. One is a GM A6/STV system just like early C2's.

3. 32 degree air out of your vents means the evaporator is operating in the 20's and is too cold. At that temperature in high humidity you will freeze the evaporator and risk slugging - when liquid rather than low pressure gas is returned to the compressor and can hydro-lock it.

The idea that 134 is not as "cold" as 12 is mostly urban legend. It is true that our old systems were designed around the specific chemical properties of R12 and that there are operational differences (such as higher high side pressures) but it is meaningless in a hobby car.

If your system is tight and full of R12, leave it be. If you have a system that leaks a bit (needs a charge every season or so) convert to 134 and save yourself some money and time (it takes to find someone who has or will reclaim R-12).

Dan

Stan's Customs

Well...there you have it. Two different opinions...and I respectfully agree to disagree as well.

I have lived all over Texas where hot is really hot for the past 45 years...and I personally have never seen a good retrofit, at least by my standards.

Nor have I ever had a retrofit 134-A system bring down temps as quickly as a R-12 system....

...but this is a long overdiscussed subject, akin to beating a dead horse...as some would say.

So only a side by side comparison will determine the answer. I have a 1992 Caprice that I have serviced since it was new and until recently was driven by my elderly mother.

I'll put it's R-12 a/c up against any 134-A retrofit system. I'm live in the DFW (Dallas/Fort Worth) area...and maybe we could determine what is an urban myth and what is not.

A nice 100 degree day would be preferable and we can have a barbecue afterwards at my air conditioned home shop....or have a Corvette car show at my manicured, partly shaded, fenced property across the street not far from Eagle Mountain Lake. Sorry, no booze though.

It would be fun...and after the a/c results it can be a Corvette (are whatever you bring) show and tell.

Maybe some of our Corvette friends from the southern Texas metroplexes like Austin and Houston could make the drive up....I've even got a few extra beds for over nighters, and plenty of secure overnight parking. (...of course our Florida friends, and others, are welcome too, and will get first dibs on the beds if they made that long haul.)

This suburban semi rural location is also on a road that local Saturday cruisers take around the nearby Eagle Mountain Lake dam and back. So we might have a little company from fellow enthusiast as well...especially if they see a bunch of vintage Corvette classics sitting comfortably in the shade "looking cool" . (pun intended, lol!)

So what do you think guys? Just say the word and sign up if interested...I'm thinking early August would be about right.

...Stan

Powershift

What system do you have?? Why do you want to change??

There should be some good info in the C2 FAQ and C2 archives to help answer this question, since it has been asked and answered a few times already. But provide some more details and we can further assist you.

You will possibly lose some cooling, but you may not notice the difference, especially in Conneticut.

I believe that OEM automakers are now phasing out 134a refrigerant and going to HFO-1234yf. So everything continues to change with time.

Larry

954rider

R-12 to R134 conversions are standard practice today because of the unobtanium or R-12 and R134 is like bottled water, its everywhere.
The only differences between the 2 systems are that the R-12 uses a different oil which is 'pushed' thru the system, while the R134a oil mixes with the Freon to travel thru the system. So make sure you try and drain as much of the oil R-12 oil from the system as possible and add an equal amount of R134 oil back into the system.
As far as the difference in cooling efficiency, there isn't much of a difference as long as you have a properly operating system.