re: Ice, Ice, Ice, Baby: Milano AC retrofit

[Joe Elliott <jee@domain.elided>]

My situation is similar to Biba's.  My hoses are just hanging in the 
engine compartment, exposed to the air.  The hot heat exchanger is in 
a box in my grandparents garage, along with my two York compressors. 
But I just ordered a compressor and a dryer from a Milano from Alfa 
Parts Exchange.  The AC wiring in my car has been screwed up though, 
so I need to fix that before I go any further.  (Anybody care to 
explain those circuits to me?)  I also want new o-rings, but besides 
trying to measure every damn fitting in the system, is there anything 
I can do to get new o-rings?  Would a place like AutoZone have in 
their computer a list of the o-rings needed for an '82 GTV6?  Is 
there some kind of orings.com?  What techniques do you all recommend 
for getting debris out of the system?  What about determining whether 
all the moisture has been evacuated?  And then I'll need some numbers 
as to how much refrigerant a GTV6 (pre-Tropic-Aire) w/ a Milano 
compressor needs, and how much pressure I should see, etc.

So I tried the Autocool ES-12a in a '90 Audi 80 yesterday with good 
results.  The fact that it was a Sunday, and neither the owner's 
manual or the shop manual gave the capacity of the system didn't 
help, but we eventually got it charged, at least well enough to work. 
When we were in AutoZone getting the R134a-style nipples for the 
recharge fittings, we saw some fancy gauges for only $35, so we buy 
them.  We get home only to discover that they don't include hoses, so 
we go back to AutoZone and pay $25 for hoses.  Then we discover that 
they don't include the appropriate fittings to interface with the 
car's AC system--another $30.  Then, after making the hour round trip 
to the 24-hour AutoZone for those fittings, we determine that, 
contrary to the pimply monkey's assurances, the hoses and fittings we 
purchased didn't provide us with any way to puncture the can of 
refrigerant and charge the system through the gauges.  So we did use 
the gauges to put the system under 30" Hg vacuum for 30 min (which is 
what I had a vague recollection of some AC guy telling me to do to 
eliminate moisture).  The Audi Digest came through and told us we 
needed 37 Oz of R12, and each can of ES-12a says "equivalent to 18 Oz 
of R12, we put in three cans and 2 Oz of leak-sealing stuff.  We 
hooked up the gauges and checked the (low-side) pressure between 
cans, but the AutoZone goon said not to exceed 33psi, and it was 
pretty clear that we were going to wind up well over that.  I think 
we did let a little out to bring it closer to the numbers from the 
Audi Digest, but it was still like 45psi.  Should we have measured it 
with the system off??  (We added one can with it off, then fired it 
up and added the rest.)  We ended up with pretty cold AC.  I'm 
probably omitting some critical detail, but I'll think of it later. 
I was going to measure the temp at the vents on a hot day, but when I 
showed up at the friend's workplace with my thermocouple and power 
inverter, I discovered that he had disassembled the center console to 
install some gauges, and left the cigarette light at home.  And today 
was the last genuinely scorching day we're going to have this week; 
oh well.

So is there any kind of book or web resource out there that explains 
these procedures so I don't have to go back and forth to AutoZone all 
day and just make this stuff up as I go along?

The other question is how the seemingly similar, yet cheaper 
hydrocarbon refrigerant from Duracool compares to Autocool's ES-12a.

-Joe

At 12:10 AM +0000 8/6/02, alfa-digest wrote:

> Date: Mon, 05 Aug 2002 12:46:05 -0700
> From: alfacybersite <acs@domain.elided>
> Subject: Ice, Ice, Ice, Baby: Milano AC retrofit
>
> I would like to second Joe Elliott's questions below regarding Mark
> Denovich's 'article' in #990:
>
> "Details to follow, but I successfully recharged a '90 Audi 80 with
> ES-12a this evening.  (The GTV6 is next, but it needs some major AC
> work before it's ready to be charged.)  Mark--I'd love to know how
> you determined how much refrigerant to use, and whether you pulled a
> vaccuum to eliminate moisture, etc."
>
> ********
>
> First, I'm guessing Mark went simply on the old bubbles in the sight
> glass method as he pretty well points out. I have been told that on
> especially 164's one doesn't want to overfill since there is no room for
> 'expansion'. Should this be the case, wouldn't this be the same for all
> AC systems? So when does someone stop? (And don't say, "When you need
> glasses").
>
> In my case, I'll be going from a totally empty AC system on my Alfetta
> GT. I've had the lines to the dryer just dangling there for about five
> years since I've kept the rubber plugs on the 'new' (unused) dryer
> itself. Therefore, I'm very concerned about 'purging' the system first
> before adding refrigerant.
>
> Mark, I'm a little vague on the removal of the existing 'valve core'. Is
> it on the compressor or the adapter / filling unit? And if you remove
> the valve core, what do you put in it's place? Basically I'd like to
> have everything in front of me when I start.
>
> Okay, five years ago I modified my factory original York compressor by
> removing it and replacing it with a Japanese Sankyo compressor unit from
> a mid 80's Saab from a local Pick-A-Part. True, my mounting is a bit
> off, but we'll deal with that later.
>
> I also removed and saved (most) of the oil in the compressor. What was
> saved measures 55 ml. How do I know how much oil to add? I'm assuming it
> comes in pressurized cans. How many oz. is 55 ml?
>
> I've been told the 'new improved' R-134a will work in older units
> without having to change seals, hoses, etc. While I've not checked it
> out, gather it is easily available. Should one not use it because it
> actually does harm seals, etc. or because it really doesn't cool all
> that well, or is it in fact almost as good as ES-12a and will work fine?
>
> The Alfetta GT AC system needs all the help it can get, just to get a
> breath of coolish air coming in on a hot day.
>
> Biba
> Irwindale, CA USA

At 12:10 AM +0000 8/6/02, alfa-digest wrote:
> Date: Mon, 05 Aug 2002 20:07:41 -0400
> From: Mark Denovich <mark@domain.elided>
> Subject: Re: Ice, Ice, Ice, Baby: Milano AC retrofit
>
> I was hanging my head in shame today when I drove to work... The AC
> wasn't working.   When I got home I realized the compressor wasn't
> engaging.   Happily I quickly diagnosed a loose fuse holder on the AC
> clutch relay, a little tweaking and I was back in business.
>
> My eagerly awaited response follows:
>
> > First, I'm guessing Mark went simply on the old bubbles in the sight
> > glass method as he pretty well points out.
>
> Yes and no.   I first calculated how much ES-12a I'd need to fill the
> system, based on the shop manual which states the AC capacity at 1.98lbs
> (or just about 32oz.) Convienently this works out to just a bit less
> than 2 cans of ES-12a.  As I was adding the last of the second can I saw
> the bubbles go away.   It's pretty clear when it happens.
>
> > In my case, I'll be going from a totally empty AC system on my Alfetta
> > GT. I've had the lines to the dryer just dangling there for about five
> > years since I've kept the rubber plugs on the 'new' (unused) dryer
> > itself. Therefore, I'm very concerned about 'purging' the system first
> > before adding refrigerant.
>
> The recommended procedure is to pull a vacuum on the system to check for
> leaks, to remove any water present in the system (and anything else for
> that matter.   My system had still had R-12 in it, which I had removed.
>
> > Mark, I'm a little vague on the removal of the existing 'valve core'. Is
> > it on the compressor or the adapter / filling unit? And if you remove
> > the valve core, what do you put in it's place? Basically I'd like to
> > have everything in front of me when I start.
>
> The R-12 fittings use a schraeder style port/valve (just like a car
> tire.) The little nipple thing in the middle is the tip of the valve
> core.   They make a cheap little tool for unscrewing valve cores.  You
> need to emove the one from your existing low pressure R-12 fitting,
> because the LP R-134a adapter fitting has it's own valve core.
>
> > I also removed and saved (most) of the oil in the compressor. What was
> > saved measures 55 ml. How do I know how much oil to add? I'm assuming it
> > comes in pressurized cans. How many oz. is 55 ml?
>
> I have no idea how much oil you need.   But 55ml is 1.86oz
>
> > I've been told the 'new improved' R-134a will work in older units
> > without having to change seals, hoses, etc. While I've not checked it
> > out, gather it is easily available. Should one not use it because it
> > actually does harm seals, etc. or because it really doesn't cool all
> > that well, or is it in fact almost as good as ES-12a and will work fine?
>
> I think it's not that R-134a harms seals, it's just that it leaks really
> easily.  I think R-134a kits now include goo to help seal the system
> from the inside.   Factory and high quality retrofits use special
> barrier hoses and special seals to combat leakage.
>
> I believe it's a thermodynamic fact that HC based refrigerants are
> superior to R-134a (sorry I don't have a good reference for this, but
> have seen it quoted in many different sources.)
>
> 	--Mark
--
to be removed from alfa, see /bin/digest-subs.cgi
or email "unsubscribe alfa" to majordomo@domain.elided