Cosmo Kramer

My guy in Kitchener will charge about $80-ish for a recharge. He said changing over all the o-rings and stuff is bull$hit in his opinion. He has done hundreds of them this way with hardly any problems. He just vacuums out the system really good to remove all of the old refrigerant and oil. Now if any parts are leaking then yes it is a good idea to use the updated o rings and replace them when needed.

928 at last

When it's late July, I'm in a suit, and it's just about 100 degrees on the crawl home from downtown (and I do mean crawl ...like 10 mph and stop and go). and there's no breeze......I really know that the A/C isn't working...

BTW...the igloos melt up here around the May 2-4 weekend........

srochepe

R-12 is available. In the US you need an EPA card to purchase. It ia also not cheap. WIth R-134A you do have to do some modifications(I believe,928 international has a good description on their web page) Also 134A is about 17% less efficient than R-12. I was discussing converting with an automotive A/C mechanic a while back and he strongly recommended Freeze 12 which he says is a drop in substitute.

Imo000

and I strongly recomend to stay the hell away from that $hit. If you have any leak, it will destroy the compressor and pretty much all blended refregerants are butane based and very flamable when atomized. There is a picture of a 928 around here that had a AC hose leak that cought on fire.

rgs944

I did not know there is a fire risk with freeze 12. I have thought about it before but stayed away from it because of all the unknowns. Glad I did. Everyone has their own opinion on what r12 does or does not do to the enviorment, but I think it is pretty clear it is the best refrigerent for you and your car.

dprantl

That right there is exactly why so many people think that R134a conversions are crap.

1) O-rings designed for R12 are a different material from the ones designed for R134a
2) If you are in for A/C service because the system is low on charge, where do you think that charge went?
3) Even if none of the o-rings are leaking yet and it all leaked out via crappy hoses, they are at a minimum 19 years old if original. How much longer do you think that 19 year old rubber will be able to seal 200 - 300psi refrigerant?

But the worst thing about the above method is not even changing the receiver/drier! You think by vacuuming out the system you can get all the oil out of the drier medium? It's a really good business plan though, I'm sure customers will keep coming back for subsequent recharges (best case) or a fragged compressor (worst case) which equals more $$$ for him.

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

Imo000

Yes the O rings are different but when they are already impregnated with the old oil, it creates a barrier and the R134a oil will not harm it. At least that's the theory.

Those of us that don't farm out the work, a garage will get very little money when something goes, so this guy will see very little extra $$$ from Cosmo.

Cosmo Kramer

^^^

What Imo said. This guy doesn't work on 928's mostly domestics. He is one of these guys that tries to make repairs as inexpensive as possible. Only thing he has done on my 928 is recharge my ac and bronzed a bolt into my leaky co tube port. Like I said mine worked perfectly fine for 3 yrs until the flex line started leaking and that had nothing to do with the r134.

JHowell37

Go pull the lines off a 928 fuel cooler that haven't been touched since it left the factory and watch the original o-rings crumble.

Imo000

One more reason not to touch it!

dr bob

I'm pretty happy to report that the full R-134a conversion I did in 1998 seems to still be OK.

You can look at mollinier diagrams and speculate that there's a specific percentage of lost performance with R-134a. But there's just a bit more to thermodynamics than drawing a line across a graph.

In the real world of Los Angeles traffic, in a black car with no tint, cruising center vent temps are under 20º on 95º ambient days. Humidity is pretty low here, usually less that 50% on hot days. It still takes a bit to get the car cool after a hot soak, but still see 40º temp drop through the evaporator, same as I expect with R12.


Most "conversions" are less than complete. So performance is less than ideal. You do actually need to replace ALL the o-rings. Get the right drier. Put in the correct expansion valves. Put in barrier hoses. Use the right oil (polyolester). Charge correctly. If the compressor is still good and there's no contamination in the system, S4+ cars do just fine with R-134a.

Cosmo Kramer

I must say the cars that have lived most of their lives in the north certainly have parts that deteriorate at a different rate then the ones from the south that see the high heat. When I replaced my AC hose the o-rings that were on it looked mint still. Also when I did the fuel lines none of them had any cracking at all on the outer sheath.

928 at last

That's exactly how I understood the process. And, in a perfect world, I'd be going to 134-a. However, it's not a perfect world, and if I can drop a recharge in that will last me another four years, as opposed to going the expense of a conversion when there's better things to use the budget on......
I think Dr. Bob makes a great point. in essence..."if the conversion is done correctly" it's not a bad thing. Downside is "correctly" is (i). more than a quick evac and charge, and will be a fairly expensive proposition. (ii). from what i have read, even if done correctly is still less efficient than the original as designed.
Bear in mind, I really need my A/C probably less than others south of here, but generally when I need it, the humidity is well in excess of 50%.

928 at last

Ok, this is Plan "B"

928 at last

Imre's right.

I use "Duracool" in my GMC's, but I also don't care if there's a combustion issue. (1995 units, with well over 200,000 miles).
I'd never consider using the stuff in my car.
As I understand it, it's part Butane, part Propane, and part some other "hane"
"Hanes" are explosive, or at least highly combustible. My Bic lighter uses Butane, and one of my old BBQ's runs on Propane........you get the idea.