Please advise on A/C conversion

David.Ullrich at David.Ullrich at
Thu Jul 18 16:49:51 EDT 2002

Would I do it all over again? Not a chance in hell! Well, at least I won't EVER let that idiot touch my car for anything ever again. Although he's great with my Impala, he's a moron when it comes to fixing imports. I fought with this thing for over 3 months to get the mediocre results I have. I think it mostly depends on how much work has to be done to the system.  If all that's wrong is a slight leak, I'd say fix the leak and refill with R12. Now if you have major work to do anyway, might as well convert, but make sure your shop is used to working on AUDIs, not just a good general mechanic or do it yourself. But, I'm happy that future repairs & refills won't break the bank. Now if Freon goes up any further in price, I'd say to others to go for it even if it is just a leaky system.

I ordered a can of QuickBoost earlier today. From the research I did and from a friend who is a chemical engineer and looked over the technical specs, it actually should make up to a 10% or so difference, which would put my lowest temp back down to around 42-43* (back where it was with R12). If this stuff works as advertised, I'll surely let the list know...


Too Many Toys:
2002 VW Jetta GLS 1.8T Tiptronic
1993 RX-7 R1
1987.5 Audi Coupe GT "Special Build"
1985 Chevy Impala Interceptor

-----Original Message-----
From: EPIFORM [mailto:EPIFORM at]
Sent: Thursday, July 18, 2002 3:34 PM
To: David Ullrich - 0018 HQ
Subject: Please advise on A/C conversion

Hi Dave:

It makes me a happy man to read your post which is full of great BTDT advice that
allows the reader to get an accurate perspective for what they "might be in for."
Glad your conversion is finally working, at least to a major extent and I'm sorry that
it ended up being such a expensive and time consuming ordeal for you.

Now to my question.  Given what you know now, and, assuming that your AC system
will continue to function as it was originally intended, if you were faced with the same
issues again, all else being equal, would you convert to R134a, or, keep the R12 system?

Tom Chudzinski

First you have to decide whether you can live with an AC system that will n=
ever cool quite as well as it did with R12. Audi does not recommend convert=
ing any car with the York Type compressor with good reason (some other comp=
ressors can be converted easier, but I have not BTDT with any of those). I =
had mine converted and it's been a nightmare, but worked out in the end. On=
 R12, from what I've heard, you should be getting vent temps in the lower 4=
0s if the system is working properly. The best I can get out of my R134a sy=
stem is the upper 40s and lower 50s (usually pegs right at 50, but varies a=
 bit). Plus it takes a LONG time to get there, 10+ minutes for so on a hot =
day when interior temps start high. An example would be yesterday when I le=
ft work. I hopped in the car and the vent thermometer (I just keep it in th=
ere) was showing 120 degrees. It took 10 minutes for so for the vent temps =
to drop to 60 on #3 blower setting (takes even longer on high). It hit 50 d=
egrees within another 5 minutes or so. But when it's 95 degrees out with hi=
gh humidity, even 60 degree vent temps feel pretty good! So, do you think y=
ou could live with a slightly less efficient system?

Now, onto the worst part, the conversion. First, if you are going to do thi=
s, do it right. That means replacing: service fittings, dryer, all o-rings/=
seals, and the expansion valve. Then flush everything (have to remove the c=
ompressor to flush it). Now evacuate for a minimum of 4 hours and make sure=
 it will hold a vacuum, now refill with ESTER oil  and fresh R134a (ester i=
s R12 & 134a compatible and it is a good conditioner of seals and o-rings) =
and keep you fingers crossed. One thing to keep in mind, R134a molecules ar=
e much smaller than R12 and will find even the tiniest ways to leak out. So=
 if your hoses are even marginal, those will have to be replaced too. Doing=
 a R12 to R134a conversion properly is pretty expensive.  My conversion inc=
luding a new high pressure flex hose and all the things above was over $700=
. Others may tell you to just go to your FLAPS and buy the $35 conversion k=
it. Sure, it might work, but from what I've experienced, it won't work well=
 or it won't work very long. One other thing, make sure your radiator fan i=
s healthy (works on all speeds if multi-speed and pulls well). It would als=
o help to put a pusher fan in front of the AC condenser to added air-flow o=
ver it.

Overall, I guess I'm satisfied with the results. It works adequately and wi=
ll make future recharges dirt cheap when compared to R12.

Well, sorry for the novel, but HTH, YMMV. Good luck.


Too Many Toys:

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