My 1993 coupe was made in mid year, and wouldn't you know it, it came with A12 refrigerant. It worked well for many years. Only needing a charge once. I say it worked well, the truth is, it never worked really cold. I could stay cool on a hot day if I pointed the vent at my face. I attributed this to all the glass. Makes a greenhouse effect. I wish to charge it again. Is there a way to do this without dropping the big coin to convert over to 134? There are some alternatives sold on ebay. Has anyone had any experience mixing anything with A12? The system quit working a few years back after one of its year long periods of being disabled for over a year. I feel like there is a good chance that one can, maybe 2 should get it going again, unless there is a leak I don't know about. What is the best way to get my AC working again without having to spend a lot, or changing out a lot of parts?
THANKS

 

No personal experience....your decision:

http://www.livjones.com/2014/05/can-...-134a-yes.html

 

I had good experiences with some stuff called freeze 12. Don’t know if it’s still available or not...

 

I just bought 3 14oz cans of NOS Interdynamics R12 on eBay for $90.

I drew a vacuum on the system for an hour, let it sit overnight to check for leaks, charged it up and now I have 40 degree air blowing from my center vents.

I too asked about, and considered converting to R134.... I did the price comparison of a new dryer, the O-Rings, the orifice that needs to be changed, the 134 refrigerant, the flush solution to get all of the old incompatible oil, and the time it takes to swap and flush everything out. It was cheaper and faster to just buy the R-12 and recharge it. The systems in our cars were designed for R12, which is a more efficient refrigerant. I have spoken to others that converted (not just Vettes) and many have said that their AC charged with R134 doesn't get as cold as the R12 originally did.

I figure as long as it is still available (R12), I'm going to purchase and use it.

Jared

 

- most C4's were designed for R12, HOWEVER, R12 is NOT a more efficient refrigerant.

I know, I sound like a broken record, but I have done it without regrets, and i'd do it again. my 134a conversion rivals my old R12. I really don't remember how cool my R12 system was, but I do remember it wasn't all that great, so it's hard to compare apples to apples. presently, my center duct temps are around 40° at cruise, and around 55° in stop and go traffic. ideally, you should increase the condenser size by 30%, but sometimes that's not possible. here's some good reading -- https://griffiths.com/ac-system-help.../r134a-vs-r12/

additional - https://pdfs.semanticscholar.org/e1f...e27937a8a2.pdf -- very good reading.

 

I would retro-fit to 134a vs deal with r12 substitutes. R12 has been out of production for decades, the substitutes can vary in composition. You will also need to find source of leak.

 

I retrofitted my 1988 C4 with R-134 and it was a fairly easy process. I bought the kit to convert it and some cans of R134 and the proper oil for the compressor. I also changed the drier while I was at it to help my system. After changing out the parts I used my Harbor Freight 2-stage Vacuum pump (~$80) to pull 28" of vacuum and then I left it for close to a week as the car was not being driven every day. When I got back to the car the vacuum was holding fine so I put the oil and then the R134 into it and the A/C started blowing cold again. Total time working on the car was less than an hour to do the actual work. It is not hard to do and not that expensive either.

I also converted my GM Pickup truck's Air conditioning to R134 and had the same success on this vehicle. I did my VW Syncro Vanagon's A/C and that was one of the easiest yet. The Germans were smart they mounted the AC equipment on the ceiling so the cold air comes down to you from the ceiling, what a great idea!

Over the years I have converted several people's cars as well as favors. I just did my Son's VW Passat yesterday and he was amazed at how easy it was to make COLD air. Having the right tools is important and Vacuum Pumps are not something you find in every garage. I do not have the capability to recover the old R-12 or the R-134 so I take the vehicle to a shop and have a buddy just remove the contents for me. This way they won't have to name a hole in the Ozone after me... The smartest thing I did was buy the leftover stock of a TRAK-AUTO parts store of their R-134 at less than a dollar a can. They had over three cases so I bought it all. I never thought that R-134 would go up that much in price.

My neighbor bought a kit off Fleabay to add to his R-12. It was a kit with three or four cans of refrigerant and some drying agent to put into the system. His car is a Porsche 944 and the low pressure fitting was under the engine and the high pressure was above the engine. Fortunately my gauges came with long hoses. I put the materials he purchased into his R-12 system and the car cools magnificently now. IF you HAVE to stay with R-12 that might be an option. I will learn what it was called and tell you if you are interested.

I would swap it to the less expensive R134 and live happily ever after if it was me doing it!

Here is hoping that your Corvette gets as cool as it can inside on those HOT summer days coming towards us.

Best Regards,
Chris

 

- from what I understand, it's against the (federal) law to import or manufacture new R12. anything you buy legally, that isn't NOS, is reclaimed and recycled R12. .

 

So 3 cans did your system? That is good information. I am thinking about doing that exact thing. Did you add oil? We have one of those charging systems at work I could barrow. I am not sure about the type of fittings. I am not so sure that it has all leaked out. I am not sure how to determine that. It would be nice to just charge it with a can or 2, but if it leaks out, that would be an expensive test. Then I start thinking it might be best to carry it to someone who does this more regularly and has all the tools. I looked at some stuff called A12, but then it says not to mix it. I go through this every year. Not wanting to pay extravagant amounts of money leads to indecision and indifference. I wind up riding with the windows down for another summer. It gets hot in South Alabama.

 

I did not add oil, from the research that I did prior to doing this I found out that drawing a vacuum on the system will not remove the oil. My system also showed no sign of a leak anywhere and attributed the lack of refrigerant to it being a 31 year old car and it slowly seeped out from somewhere. The system did still have some pressure in it, just not enough to kick the compressor on.

I should have been more descriptive in my previous post when I said R12 is more efficient than R134A. R12 will do a better job of cooling when used in a system that was designed for R12. R134 used in a system that was designed for R12 will not do as well of a job without modifying the system.

A previous poster mentioned 55 degree air at idle, and 40 degree air while cruising with R134. I currently have 40 degree air at idle and could probably hang meat while cruising. I had to turn the AC off yesterday on my way to work because I got too cold. Black car, black top, 76 degrees out.

Three 14oz cans fills the system completely. 44oz is "My" systems total capacity, 8oz of oil and 36oz of refrigerant. Check the capacity of your system before you go forth with purchasing refrigerant.

This is all my own experience, others may have had different experiences. I decided to go with R12 because it was pretty much a "one step" operation.

Jared

 

I have experience
Bought a kit like this from Walmart a good 20 years ago because the r12 in my system leaked out after a recharge.
It still blows cold to this day and has never been touched

 

Totally agree with that. However, since you can't change the system, there isn't much you can do with R134A except run it off a system designed to do R12. I tried but you cannot switch out a 96 condenser which is going to make it more efficient by the design of the condenser.

But is that a good test of the system? I would think that a clean condenser running in 90 plus degrees of humid air in stop and go traffic is a much better test.

 

-- 76° is no test. 76° is top down weather -

my center duct temps, 40/55° are based on 90° days (with humidity) here in florida. running a "glass" top in stop and go traffic also taxes the system. that green house effect is a biotch -

by todays standards, the AC systems in C4's were not all that efficient. larger condensers, better fans and blowers, ducting and insulation would definitely help. bottom line - you can't get expect 2019 results out of something designed in the 80's. the technology just wasn't there -

 

Actually, I love the 3rf Gen F-body because it had a solid roof. My first and last new car. I specifically asked for a solid roof. I always run heat or AC and never opened the window other than at a drive through. AC is a deal breaker for me. Even now I threw away the glass roof for a fiberglass one.

Neither of those 2 cars seems to keep as cold as it is was before the conversation. Seems like a good 5 minutes longer to get to 65 to 70 in hot humid temperatures in the summer when I timed it eons ago. I don't have the test results but it didn't seem to work as well in traffic jams.

I don't. I was comparing 1991 R12 to R134A. I do a total conversion. New compressor, right oil, etc. Professional job. Clean up the friend's condenser with R12 ve my conversion on the C4 and my pre R134A to R12 in the F-body.

 

I respectfully disagree.....








The numbers don't lie....R12 in an R12 system.

 

you need to re-read some of the posts, and most of the thread. we were referring to a C4's converted system - R12 to R134a. to clarify, don't expect 134a converted results in 2019 out of an R12 system designed in the 80's. BTW, you have some impressive numbers there (from that little analog gauge), is that an actual corvette center duct? looks nothing like my 85 - ??? as efficiency goes, even on its best day, a C4 system doesn't hold a candle, or should I say, an ice cube, to a modern day 134a system, the design and technology is just not there. as I said, my converted 85's system rivals (from what i remember), my original R12 system. this topic can go on in a never ending pissin' contest, so i'm outta here - -- peace and stay cool my friend -

 

This is an R12 system on an old 87 Raider. It was around 85 outside. R12 way better the 134 anything. That's at idle too.

 

Joe - I meant no disrespect with my last post, and I completely agree 100% with the clarified version of your of the original statement. From what I have read on the topic over the years, and the numbers I have seen other members post, I have drawn the conclusion that converting an R12 system to 134a will not give the performance that the system was originally designed for when using R12. A converted system will blow "cool" air, but not cold air.

The numbers that I posted were from my '76...which was even older technology.

Below is a shot from my '87. I didn't take a screenshot of the weather that day, but it was comparable to the weather on the day I snapped the stats from my '76. On the 87, I actually had to add an adjustable low pressure switch after installing a new parallel flow condenser. The parallel flow condensers are so much more efficient at thermal transfer than the tube & fin condensers that after charging the system to the recommended pressures in the FSM, I was getting icing on the evaporator core. Raising the cut off slightly on the low pressure side fixed that. Temp at the center vent was nearly dead on with that of the '76, both using R12.





My intent was merely to point out to the OP that keeping his R12 system original would give the optimum performance the system was designed for.

My current '86s performance is a mirror image of the picture above.

On a side note, I would love to see the results posted from someone who has converted one of these R12 systems to R134a AFTER having changed the condenser from tube & fin to parallel flow. Based on my condenser experience noted above, I believe that would have to make a difference in cooling...and all for the better!

Stay cool my friend!

Dave

 

I think I'll keep my R12 system as it is
Thanks guys

 

Dont mix them. There is a finite amount of R12 now and what gets recovered and reused helps an end user. Mixed gasses are never able to get unmixed so the mess gets destroyed.