ROG100

Nicole,
R-413A, aka ISCEON 49, is a blend of R-218, R-134a, and R-600a (9/88/3 percent by weight). Since 88 percent of R-413A is R-134a I would stick with R134a if you need to change from R12.
Roger

Andre Hedrick

The system was empty and needed an O ring replaced too.
Also if it leaks down in the first year, I get free refills under warrenty.

UKKid35

Changing from R12 to R134a requires significant work (expense), whereas Isceon49 (brand name for the blend as Roger describes) is a drop in replacement that is extremely cost effective.

Autofrost which is available in the US is similar although not made by a major multinational. Some time ago George Goble, the developer of Autofrost, was kind enough to answer in detail a question I emailed comparing Isceon40 and Autofrost - impressive service!

ROG100

Hi Paul,
So are you saying that the 12% of non 134a makes all the difference in Nicoles case?
No changing of O rings or expansion valve or connections.
If that is the case then Nicole needs to consider it.
I am going to stick to R12
Roger

Andre Hedrick

John,

Try to sneak that in to California, the Green Freak Police will terrorize your life.

joejoe

I also did not mean to step on any toes/feelings here. Nicole asked if anyone has used a substitute for r-12. I have, and my experience has been good so far. I will say I have 90lbs of r-12 and all equipment for recovery, evacuation, leak testing, guages, digital scale etc.. As the autofrost was cheaper (and I was curious) I used it for leak detection with the dye and black light. My systems were gone through (by me) with all o ring replacement. I have found the pressures about 15% lower than r-12. Autofrost is a blend of r22, r142B, r600A.

Nicole

Thanks, joejoe. This shows that we actually do have options here, which work just as well with less environmental risk, and have the potential to save money along the way. What's not to like about this?

Right now my system is charged with R12a nd works, but we suspect there is a slow leak. Eventually I'll have to evacuate, fix whatever needs it, and recharge. I will then consider the Autofrost.

123

First someone concluded that R12 was bad for the ozone layer, and therefore the environment, so it was banned and replaced with R134.

Then someone (same guy?) concluded that R134 is a greenhouse gas, and therefore bad for the environment, so it's in the process of being banned. It looks like the replacement for the R134 will be "environmentally friendly" R744.

R744 is CO2. Did someone say CO2?? Yes, you know, that stuff Al Gore's busy running around telling everyone is bad for the environment.

I think I'll just wear shorts and keep the windows rolled down. Hopefully shorts aren't discovered to be bad for the environment for a while.

http://www.umweltbundesamt.de/uba-in...6/pe06-040.htm

http://www.behrgroup.com/Internet/be...572350050355F?

Nicole

If you compare a brand new Porsche with a 356, you'll probably find that not only is the new one much more environentally friendly, but better in almost any respect. Today, you could not even register a "new" 356 in most parts of the world.

There will always be something better than before. And sometimes we don't realize it until we try it out...

SharkSkin

Figured I'd jump in about now and mention that R134 is not necessarily going to work in every shark. OB owners take note: I did a 134a conversion and found that it was marginal. Two key factors: My fan is not wired to come on with the AC like later cars and I have a less efficient condenser -- it's the older round-tube style:



It seemed to cool fairly well when moving at 35+, but it just seemed overpowered by all of the glass, black interior, etc. I finally switched back to R12 and it works fine. Not freeze-yer-fingers-off cold unless I've been moving for a while but now I'm happy with it.

Hopefully I don't need to consider an alternative until after I get a higher output alternator -- which will allow me to tie the fan to the AC without problems when I need lights/wipers/defroster -- but in any case I think a later condenser will be needed.

RED SHARK 1990

Hello members whats the big cost on the r12?i saw at INTER AUTO PARTS IN SAN DIEGO off Convoy street here ,and they were selling them for 12-14.00 dollars a can.Anyone interested just call them,i asked them about r12 not too long ago.

mj1pate

[QUOTE=Nicole;

So, I really wasn't looking for info on how cheap R12 is - I was hoping that someone out there has tried a good substitute (not what Louie used) and had anything to say about it.
[/QUOTE]

I've been looking for options as well and I'm sure most owners of these 20+ year old cars will come to this juncture. Those more experienced with the 928 A/C system have described the range of the tasks to include not just the receiver/dryer, seal, barrier hoses and or compressor upgrades. In some of the pre-S4 types, the condenser, condenser fans and condenser fan on/off cycling control may all need modification as well. This is no small thing to financially limited, committed DIYers.

I would like to plan to upgrade to R134a, in the same way as I plan to change motor mounts, OPG, service the transmission, and refresh the injectors/intake. But the aforementioned will be replaced by stock equivalence and have been done by quite a few before me. Upgrading earlier 928s to R134a requires a fair amount of A/C expertise to the extent that modifying a stock system is safe and reliable. My inclination is leaning towards a complete equipment test/repair of the R12 system accompanied by a methodical vacuum capacity validation.

Upgrading new car production to use an enviro-friendly refrigerant is no-doubt necessary. Responsible conduct doesn't necessarily require upgrading "historical" cars to R134a. Ensuring that aging cars aren't recidivist polluters takes a major, affordable step. Not to mention the real expectation that a properly equipment-refreshed stock system will work is pretty desirable.

Mike

ShawnSmith

One thought: The R-12 in your 928's AC system already exists. One of the safer places to keep it from escaping into the atmosphere is a well maintained 928 AC system. If you swap out your R-12 for some alternate coolant, the R-12 which was in your car now gets recycled and likely put into someone else's R-12 vehicle of unknown level of maintenance....

Assuming your AC system is tight, there seems little "green" motivation to pull the R-12 out of it unless you have a plan for how to destroy that R-12.

Podguy

Guys and Ladies,

It is a fraud. I like to be green as the next person - I drive a Hybrid, heat with Wood Pellets and use solar heat for the pool. All these are commerically viable and enviromentally friendly.

The conversion to R134a was driven by Dupont whose patent was running out on R12. Does anyone one really believe Ronnie (once you ahve seen one redwood you have seen them all) Reagan and Thatcher were environmentalists? Yet both gave speeches on the danger of ozone depletion and the potential of skin cancer killing everyone. Increased skin cancer rates were eventually traced to reformulations of extended sun tan lotions that blocked UVA but not UVB. It had nothing to do with the ozone hole which has sicne fallen out of favor. Junk science.

The entire change in the law was based on one obscure scientist's doubtful and non-peer reviewed work. Now when the R134a patent is running out Dupont is pushing an even better and more environmentally friendly refrigerant. Surprise the same reseach is now being used to show how terrible R134a is. Go figure.

Anyway there is plenty of R12 around. it can be bought at a reasonable price if you look carefully. These systems are designed to use R12. If you convert to R134a you should replace the hoses. R134a hoses are lined to prevent leaks. R134a requires a larger capacity evaporator to get the same level of cooling. Some claim the rear A/C will never blow cold enough with R134.

My 78 is still blowing cold from the initial factory charge. Change out the hoses, use good O rings and get a good pull down and the system will work fine for years and years.


Dan the Pod Guy

dr bob

The R12 'ban' is hardly effective, mostly because only a relatively few countries signed on to the Montreal Protocol. Most beyond the US were bullied into it when the US threatened to ban import of cars and appliances with R12 in them. Dupont still manufactures and sells R12 all over the world, except in those few countries. There are more than a few wild theories being reported as facts, without substantiation. "Global Warming" as a direct function of human generation of atmospheric carbon tops my list of those.

Obligatory content: I converted my S4 to R-134a about 8 years ago. I've added 2 lbs of additional refrigerant during the intervening years, since the car sat a lot and the compressor shaft seals went a little dry. I drive it more now and no problems.