virtue4u

I would appreciate your thoughts or tips. I don't want to change out any equipment. If you don't agree with the conversion, then is R12 still available in the can? I have the adapters to fit R12 cans, but I can't find any of it in the auto parts stores. Thanks in advance.

Smokehouse69

I'm going to point you to the site that I have learned the most about airconditioning and alternative refrigerants. R-134a is a popular replacement, but it isn't the best for our old R-12 type systems. They were designed for R-12 and work the best with R-12. Perhaps the best replacement for R-12 is a mixture of isopropane and isobutane, but it isn't certified for use in motor vehicles, because it is flammable. It is sold under the name Envirosafe (I think.) It is used in many other countries in cars, but the DOT says we can't use it.
Check out http://www.aircondition.com Look at their Alt Refrigerant forums, ask a few questions and you'll get a bunch of answers. Pretty friendly folks overthere, not as friendly as here, but close.

Tom73

Want R-12 at a reasonable price? Just check out eBay. Do a search for "R-12".

tom...

joeveto

The R-12 is expensive, and it's going to keep getting worse, not to mention the environmental impact, should it escape your system.

I've talked with guys who've made the switch, and they like it a lot. Some guys have even reported better performance than with the old stuff. My Vette guy will switch everything over for about $400.

There used to be a guy on this site who did a really nice step by step, but I don't remember his handle or site.

Anyone else remember who he was/is?

Tom73

I don't know, seems to me the price will be coming down. Yea, it is not being made any longer, but there are tons of it out there in warehouses. Fewer and fewer cars are using it due to conversion or being taken off the road so the demand is rapidly dropping. Won't be long before the only ones with a demand for it will be collectors.

tom...

Carl in LA

And would that be ZWEDE??? I recall he lives in Dallas area so I am positive he knows something about air conditioning!! :D :D :D (hey, I paid my dues in Austin for thirty years... I can talk about heat)

eeeticket

Tom is right the demand of R-12 is falling. In the refrigeration business there are several good less expensive alternatives to R-12. The last 30 pound cylinder of R-12 we bought at work was about $950. Way to much considering most alternatives are about 1/3 the price. That will probably be the last one we buy. I think that after while the only people who need it will be car guys.
That said, my personal favorite alternative is Hot Shot from ICORE International. No it isn't a simple drop in, you need to switch to a barrier hose. If you were going to replace hoses anyway it might be worth checking out. I've used it in two of my vehicles, and it works great in extreme temperatures.
And i'll say it before Tom does, you might not be able to get it in the middle of nowhere. so if the air goes out in the middle of that cross country road trip, you may be sh!! out of luck.
Hey Tom any thing i forgot :lol: :lol: -- We've had this discussion before.

eeeticket

Carl is that where Captian Kirk fought the Gorn creature on Star Trek? :lol: :lol: :lol: Ya i'm a closet nerd.

virtue4u

The auto parts stores sell air conditioning conversion kits for $30. Will these kits not work on a 77 without a major conversion of the air conditioning components?

One GM A Tech

We do this at the job all the time. First you cant by r12 without ID (certification) The other is I have not seen the small cans in ages. On that year vette it is straight forward to convert. the only part that I recomend to replace is the accumulator. The reason is the disscant bag inside of it . get a new one they are fairly cheap. Pull the ac compressor off and drain it as much as possible. I say this because you dont know if Bubba over oilcharged the system at any point in time. Assemble everything back together. Pull the system to vaccum 29hg is prefered depending on where you are different altitudes will veriy the readings. Make sure that the system is holding vaccum. This is the biggest mistake the guys make. I assume that you have access to a set of gauges and an evacuation pump. shut the pump down close the gauges and post to the forum how well its going this can take up to a half hour. now go back if the system is holding vaccum you know that it is not leaking now you can go about changing the freon port adaptors. Oil charge the system then freon 134A charge to spec. The good thing About the new 134A is that it comes with a built in dye that is highly visiable when leaking out. Funny thing is that I used to get a lot of people complain that they have had recharges done unly to recharge again next season with R12. This is not the nature of the gas. This is the nature of the lazy tech that does not check for leaks before charging the system. R12 is an excellent refrig gas. have the system repaired or checked correctly at a reputable place and you should enjoy many years of artic like air. There is the other thing and that is to make sure that all your vaccum accuators for the ac system are working right and that the duct work is hooked up right :yesnod: :chevy :seeya


[Modified by One GM A Tech, 9:29 AM 3/14/2002]

Shark79

A friend of mine converted his 82 to R134a. It wasn't that hard, other than replacing the drier that appears to be a b*#ch to get at. It cools fine and that's a big job here in Georgia! Mine works but leaks freon so that's my next project. Right now it's recharged with something called Freeze12 and when charged works fine.
Here's a link I saved for future reference http://www.corvetteforum.net/c3/zwed.../ac/acmain.htm

zwede

I still have the pages I wrote when I did my R134a retrofit. Click on the link in my sig and you should find it.

The only thing I would like to add to the excellent info above is that if you live in a hot, humid climate you may want to adjust the AC after the R134a switch. Reason is R134a has a different pressure curve compared to R12. If you just drop in the R134a, it will not cool as well as R12. The vent temp on my 71 was 52F @ 90F ambient. After adjusting the POA valve it dropped to 42F.

On early TXV systems, the adjustment is in the POA valve. Turn the little screw inside 1/4 turn CCW. Note that it is only adjustable with the system discharged and the hose removed, so better get it right the first time. :)

The later CCOT systems are adjustable with the system charged and operating. Hook a gauge to the low side and adjust the pressure cut-off down about 3-4 PSI. On the CCOT system you can experiment with the adjustment to get the lowest temp possible without freezing the evaporator.

Kingt

Before you convert to R134a check out what is described as a drop in repalcement for R12. It's called Freeze 12. Search for sites on the WEB. I also have a 77 that I'm restoring as we speak. I purchased a case of Freeze 12 over the internet over a year ago for this purpose. I have not tried it yet. I've heard some good reviews however. You'll also have to purchase the correct fittings, they aren't very expensive. And, you don't need a license. I purchased two cans of R12 last summer @ $33.00 per can! OUCH!
:flag

Tom73

Be careful when using the term "drop in" as it means different things to different people. Many see drop in and assume that you can just add it to the R12 system. Per the EPA you cannot mix refregrents. So you still have to purge the system first.

By the way, Freeze 12 is 80% 134a. The other 20% is HCFC-142b.

tom...

vettesite

zwede's step by step procedure is similar to what I did when I coverted to R134a about 2 years ago and my A/C works great. Here is how I did it (see zwede'd page for details):

* Evacuate old R12 - took it to Jiffy Lube
* Install new accumulator/dryer
* Install new hose (old and crusty)
* Install new compressor (it blew up and leaked all over)
* Install Retro R134a kit parts (includes PAG oil)
* A/C shop flushed entire system (condesnsor, evaporator, etc..)
* A/C shop adjusted pressure, added R134a and pressure checked system

Feels good on a hot and humid summer day! :yesnod:

zwede

I'm not a big fan of the blends such as freeze 12. It's hard to find a shop that will touch it. Most shops have a tank for R12 and one for R134a. They will not do anything with a freeze 12 system, as it would contaminate their tank.

Another problem is that the 2 components in Freeze 12 (or any blend) have different densities which means they leak at different rates. If you have a slow leak, let's say it leaks a pound over a year, you will have to evacuate all of it and replace. If you just top off, the ratio will be off and results unpredictable.

virtue4u

"My next plan was to take it to a better shop, but my fiancée said "you're going to end up doing it yourself in the end, so just do it". Well, I guess this was a good time to learn about AC"

That's exactly what happened to me. I have brought my car twice to a shop. They claim they cannot find the leak, so once again if I want the job done right I will have to do it myself. After reading your comments, I think I may stay with R12 (if I get certified) or use a product called Enviro-safe. Your thoughts on the cost of certification or using Enviro-safe?

zwede

Well, my thought of the blends are above... As for the certification, I hear it's pretty easy and costs about $20 online. I didn't bother getting certified myself as I have had no problems with R134a. I can buy cans of R134a for $4, so that's what I'm using in my cars.

I need to convert my newest acquisition, a 83 Caddy Deville. The R12 charge is low.

One GM A Tech

That is so lazy of these guys calling them selves A/C techs and they cant find your leak. Let me not get off on a rant about bubba A/C techs. If they could not find your leak by the usuall means dye check and ultrasonic testing and they did both these test u need an evaporator core. it is the only part of the system that is fully enclosed. As far as certification goes it can be had by taking an open book test from a company called mac,s. 20 or 30 bucks. r12 can be had on ebay like the forum members have already posted. Something that must guys dont know is that there is a lot of bogus R12 floating around out there so purchasing that on line is really a shot in the dark. :seeya

virtue4u

In referring to "bogus R12," are you saying that the "R12" sold is not really R12? Is there a way to determine the contents in a can?