A/C Retrofitting

[Steinbru@vnet.ibm.com.spamsux]

Ref:  Your note of Sat, 3 Oct 1998 01:27:44 -0400 (attached)

Adam,
Don't do it, at least not yet.  As I understand it, the biggest
problem with the "simple" conversions is the reduced efficiency
of r-134 and the residual chlorides in the oil and lines, which
convert some of the new oil (pae?) to solids which seize the
compressor in a variable (but often short) time.  There is a
good "ac conversion" discussion somewhere (check via dejanews).
Watch especially for Goble's posts there, he knows this stuff.
Also, there are a couple of good sites to visit in the old post
I attached below.

In partial answer to your questions:
1) opinions vary, most replace them.  I have "recovered" a few by
using a heat gun on them for an hour while the system is under
vacuum.
2) The evaporator ices up and the "cold" stops flowing
3) Absolutely, r-12 and r-134 use totally different oils, and
actually I'm not sure you can ever flush it well enough.  The
residual chlorides become part of aluminum components such as
condensors.
4)Evacuation is essential, go read up on how phase change
refrigeration systems work.
5)Blow out?  Nitrogen?  Confer with a specialist --heh heh, try
the guy at your local Jiffy Lube for starters.  Some don't know
much more than you, but they have a procedure to follow and
will go over it with you.  Beware the sales pitch.
--Gary

----------------------------- Note follows ------------------------------
Date: Sat, 3 Oct 1998 01:27:44 -0400
From: adamnelson@juno.com
Subject: A/C Retrofitting

Just today I saw an R-134a retrofit kit for sale at a local parts store.
The kit simply had a hose, two fittings, oil, and two cans of 134a, all
for $26.95. Since I own a formerly R-12 car (I say formerly because all
the freon is gone), I was interested. The kit makes no mention of the
reciever/drier or flushing and pulling a vacuum. This left me asking
"could it be this easy?"

I had always assumed that the reciever/dryer had to be replaced when
retrofitting. That seems to be the position of many mechanics. My parents
just spent $1000 on their repair and retrofit. The reciever/drier was
$190 of the bill. My car cost a whopping $850, and the blue book is
hovering around $1200. While it may be distasteful to many Q-List
members, some Audis make great beaters! With this in mind, I didn't feel
ready to begin what would be at least a $300 repair. The opportunity for
a cheap alternative is very tempting. Here are my questions:

1. Is it necesssary to replace the reciever/drier?

2. What can happen if I don't?

3. Is it necessary to flush the system, and how can this be done.

4. How important is it to evacuate the system?

I was figuring I could at leat blow out the system with a big can of
Dust-off (nitrogen), but beyond that, I'm lost. Any help would be
appreciated.



--ATTACHMENT-------------------------------------------------------------------
Date: 5 June 1998, 08:22:21 EDT
From: Steinbru at vnet.ibm.com
To:   quattro at coimbra.ans.net

Re:   how do you make the a/c colder?
Ref:  Your note of Thu, 04 Jun 1998 17:32:13 -0500

I tried to post this before, but did not see it:
The first URL is a good hackers guide, best I've seen.
The second more conventional.  Notice the reference to
isobutane mixtures in both (sources listed in first).

http://www.vettenet.org/acfaq.txt   R-12 replacement FAQ
http://www.startext.net/homes/ggoodspe/ACCONVRT.HTM   R-12 to R-134a
                                                Refrigerant Conversion
R134 IS NOT an iso-butane/propane mix BTW.
--Gary