ROG100

We have lots of R12 for $23 a can.

928man

Many thanks everyone the A/C issue is very complicated but I appreciate all the suggestions and help not sure what I will do but I will go slowly with it.

928man

Has anyone ever heard of R12A Refrigerant, and used it in their 928? Can be bought without a certificate but I don't know if it's compatible with the R12 system.?

dr bob

Stick with genuine R-12 or R-134a. That way someone else can work on the system when you can't or don't want to.

My R-134a conversion still freezes the fingers on the wheel a dozen years after I converted to R-134a. It works well enough that I don't even think about using R-12 in it. I have cylinders of both. At this rate I'll probably end up paying someone to haul away the R-12 cylinder as hazardous waste or something.

Andy E.

High Pressure = High Temperature = Reduced Component Lifespan due to Fatigue & Eventual Component Failure

Dan, how do you think the rest of the components within the system are dealing with this added high pressure? A sealed refrigeration system is not designed to leak and proof of this can be seen in some of the older American cars of the '70's that were scrapped many years later and their A/C systems still functional. The same can be said about your home A/C system and your kitchen fridge.

If your engine oil temp was running above the norm near critical temperatures, would your feelings about letting it go that high and not worry about it, still be the same as your theory on running high head pressures? Probably not.

In the late '90's, most vehicle mfrs raced to implement the new refrigerant-134a into their vehicular HVAC systems. The rush into the 'new' gas meant minor changes to the overall components (types of materials used) leaving behind the same fin-tube condenser that was used in the R-12 systems. Early 134a-equipped cars suffered from insufficient cooling during heavy summer months. A few years later, the factory realized that the system efficiency was reduced with the new refrigerant and the condensers were later enlarged to increase capacity.

FYI, R-134a was not fully tested at the time and found years later to be harmful to the environment as well. Are you aware that plans are being followed to phase out R-134a?

On a recent Treffen to Germany (Fall Treffen 2009), I spoke with a retired Porsche exec, during supper one humid night, who balked at how we 'Americans' cannot live without A/C and that the German people hate it. With sweat pouring down the sides of my forehead onto my sweat-soaked shirt, I calmly looked up at him and respectfully said, "Now I understand why all of Porsche's older A/C systems never functioned properly or even functioned at all". The Treffen participants subsequently laughed knowing how true this statement really was. The retired exec also cracked a smile but hid it well under his bushy mustache.

blown 87

QFT

dprantl

So my A/C system will last 10 years instead of 20, well that's good enough for me. If I was really that worried about it, I would stick in that custom parallel-flow condenser I have sitting in the garage.

Dan
'91 928GT S/C 475hp/460lb.ft

blown 87

I have seen them go out far sooner than that, they go out faster than that with R12 at times.

dprantl

Yeah, but then again my wife's former 968 with an ancient tube/fin condenser, R134a factory fill and a 10P15E compressor was still good the day we sold it a few weeks ago and that system was never touched except for a clutch replacement due to the rubber in the clutch separating (and an A/C relay if we really want to nitpick). That would be 17 years. YMMV I guess. Oh, and the reason the clutch rubber separated? Because that car would freeze the crap out of the evaporator so fast, every 20 seconds (max) the freeze switch would cut the compressor off. All those on/off cycles is what eventually did the rubber in (and the relay too). Having R12 in that car would have made no difference at all except for the lower high-side pressure.

Dan
'91 928GT S/C 475hp/460lb.ft

hacker-pschorr

I know a person with a reliable MG - there are exceptions to every rule

You've already done the conversion, good for you. Why do you have to come in there and poo-poo a real expert on the subject trying to offer good advice?

The "original" reason to convert was to "save the planet" which is now being proven to be BS, not to mention new harmful effects of R134 are coming to light. So yay, you converted and had no issues.....that doesn't mean everyone else with an A/C issue should.

Nightfly

Can't remember where, but there was some mention that R134 was being phased out because the patent owner's rights are gone. So, they need to promote a new, patented 'environmentally friendly' refrigerant. Until that patent runs out. Then we'll find out that one isn't 'environmentally friendly' either. Ad infinitum.

Andy E.

R-134a will be phased out due to it's contribution to 'global warming' and not ozone depletion as was the case with R-12.

It also seems that we'll start seing a roll-out of the new refrigerant R-1234yf in automotive air conditioning come 2011; however German automakers are still convinced that R744 (CO2 - Carbon Dioxide) may be the refrigerant of choice in the future.

Sources:
http://www.r744.com/articles/2008-06...o2-r1234yf.php
http://www.sae.org/mags/aei/6384

dprantl

Hmm, I have 6 more examples right here, I must be a really lucky guy.

Wow, seriously? So I am not a "real" expert on this subject Who says converting to R134a is not good advice? Why do you have to come to a thread and poo-poo on whoever's tune doesn't resonate with yours, when in this case you are clearly the least knowledgeable about the matter?

This saving the planet with another refirgerant story is a bunch of BS. Both R12 and R134a are harmful to the environment in one way or another, so why pay more when you can pay less? In a couple of years, new cars will be using something else. If that something else will be cheaper, I will convert to that as long as the performance is good enough to freeze up the car and it's as easy to convert as it is from R12 to R134a.

Dan
'91 928GT S/C 475hp/460lb.ft

Andy E.

The U.S. Environmental Protection Agency (EPA) approved hydrofluoroolefin (HFO-1234yf) as an acceptable substitute chemical for chlorofluorocarbon refrigerants. The chemical is intended to replace R-134a since it is believed to have far less global-warming potential. However, “1234yf” may only be used in new motor vehicles. The EPA did not approve use by “do-it-yourselfers” to recharge vehicle air conditioners pending further review on whether there is a toxic chemical exposure risk via inhalation. The agency is also considering a proposal to allow 1234yf to be used as a substitute for R-12 in new motor vehicles.

Source: http://www.sema.org/sema-enews/2010/...ac-refrigerant

RED SHARK 1990

Everyone has their own opinions and they will do what pleased them...Therefore, here is my saying if you drive bare back and roll down your windows no ozone depletion ,EPA will be pleased. You save the planet! Cheers Happy holidays , r12,r134- if you feel to convert-do it.