A/C refrigerants ... r-12 to r-134a or HC (long)

[Henry A Harper III]

Ok, I've got two cars with "alternative" experiences. In chronological
order:

1988 VW GTI 16v: purchased in 1994 with 103k, a/c worked great until summer
2001 when the R12 seemed to leak out. I did a fair amount of surfing and
decided to try "drop-in" AutoFrost (GHG-12) rather than the "known" 10-15%
cooling performance loss of R134a. Local shop recovered remaining R12 and
didn't even charge me too much (should have paid me...) AutoFrost cooled
well initially, then the small-molecule fraction disappeared through my OEM
non-barrier hoses over a period of several weeks and cooling performance
deteriorated. Limped through the rest of the summer on a recharge or two of
AutoFrost. By the start of summer 2002, it was all gone so we decided to go
for R134a conversion; new receiver-drier with compatible dessicant, POE
oil, o-ring-conditioner-in-a-can, and super-stop-leak from acsource. Again,
cooled well initially but the next day compressor front seal blew out. New
front seal from acsource.com, refill with R134a and it worked great the
rest of the summer. This year, it started out working just fine, then went
intermittent before generally failing to cool while still holding pressure.
The compressor was running but it seemed like it wasn't doing much work
(idle was compensated too high with a/c on) so I ordered a new expansion
valve through Import Parts Specialists (local to me). Evacuated an empty
propane BBQ tank, sucked the R134a into that (icewater bath helped
condense), replaced expansion valve, leak check ok, put same R134a back in,
works great again. Of course that was only a couple days ago...

1991 200 quattro: purchased in late 1997 with 79k, a/c worked sort of ok.
Local shop threw in a can of R12 in summer 1998 and that held it until the
next summer, when Wal-Mart charged a lot more for basically the same
service. It was becoming obvious that the compressor front seal was the
source of the leak, so in 2001 when all the R12 had leaked out I got a seal
kit from acsource, installed it and filled with AutoFrost. Which again
worked great initially but degraded over time via leakage of the R22
component through OEM non-barrier hoses. Summer 2002, topped up with one or
two cans of James' supply of R12, works pretty good since that's not
leaking through the hoses, but not optimal since it's not all R12 either.
If this starts leaking ever again, we'll draw on James' positive experience
converting his 200 to R134a with receiver/drier change and variable-orifice
valve from acsource.

Conclusion: AutoFrost is a bum deal unless you maybe have barrier hoses
already. R134a isn't that bad, but you do need to replace receiver/drier,
maybe/probably o-rings and orifice valve (perhaps even compressor seal!) -
but these are all relatively cheap compared to new major parts like
compressor, evaporator, condenser, etc. Our small sample size of
compressors seems happy so far with POE oil, which doesn't require the
flush and/or replacement of all system components like PAG oil. Of course,
if you can fix the leaks, then the system designed for R12 will work best
with R12 assuming you can find it at a price that isn't totally
unreasonable.

HTH,
Henry Harper
http://www.henry-harper.com  hah at alumni.rice.edu
1991 200 quattro, 117k, road trip to Santa Fe tomorrow
1988 GTI 16v, 236k, daily driver nice and cool again...ahhhh


On Tuesday, June 10, 2003 9:50 AM, MXHOWES at aol.com [SMTP:MXHOWES at aol.com]
wrote:
> I would like to get some CONSUMER input about retrofit successes or
failures
> using alternative refrigerants to r-12. In searching the web it is very
> confusing because most of the information comes from someone who has a
product to
> sell, ie. enviro-safe, freeze 12 etc. or the A/C shop owner who (like the
Audi
> dealer) wants you to believe that THEY are the only persons qualified to
work
> on your system.
>
> Let's assume:
>
> 1.  You are going to vent your old system the proper way (this subject
has
> been covered well)
> 2.  If you post to this topic, you are a consumer with first hand
experience
> in retrofitting your own car or having it done for
>      you.
>
> If you have done a conversion please state what components were replaced.
>
> Thanks, Jim
>
> 85 4kq (A/C doesn't work)
> 88 80Q (A/C doesn't work)
> 92 Astro AWD (A/C doesn't work)
> the A/C still works on all my Fords (84 & 91)