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Any one know anything about A/C?
One point I forgot to mention, I personally think it's complete BS that
134a is not as good as R-12, at least from a cooling performance point
of view, as long as the system including compressor, expansion valve,
condenser and evaporator are designed for it. My '97 Jetta, my '95
F-150 and my wife's '01 Grand Cherokee all have R-134a and they all
blow ice cold. The F-150 will actually blow so cold in just a few
minutes that it will hurt your hand to hold it in front of the vents,
just like the old R-12 systems.
John Gates
--
'97 Jetta GLX
'85 Scirocco
-----Original Message-----
From: John Gates <gatesj@mailblocks.com>
To: timjmcconnell@gmail.com; haygood@myway.com
Cc: scirocco-l@scirocco.org
Sent: Mon, 20 Jun 2005 06:48:43 -0700
Subject: Re: Any one know anything about A/C?
As I understand it what will cause the corrosion is moisture, not R134a
itself. There is always moisture in the air, if the system has been
open to the air it needs to be positively sealed, optimally the
receiver/dryer needs to be replaced (so there is fresh dessicant that
can absorb any tiny bit of moisture in the system) and fully evacuated
for a decent period of time to make sure every tiny bit of air that
could contain moisture is out of the system. At a high vacuum, around
or under 50 microns, water boils off nicely and comes out of the system
as a gas, but you need a real vacuum pump, cheapest I have found is
just under $200.
There is also something I remember about the mineral oil that worked
with R-12 being incompatible with the PAG oil that you would use in
R-134a. All oil needs to be drained from the compressor and flushed out
of the rest of the system with a specifically designed flush to really
do it the right way. Then the correct amount of PAG needs to be added,
the system sealed and properly evacuated and then charged with R-134a.
It's either the PAG or the R-134a itself that combines with water to
form an extremely corrosive acid. This is why any time you open a
system or it leaks on its own down to ambient pressure you have to
evacuate it. Otherwise the system will work great for a few months or
maybe even a couple of years but eventually the acid will eat through
the condenser, evaporator, etc and you will have swiss cheese. R-12 and
the oil they used with it did not have this problem with moisture.
The conversion kits have been reported to work OK but I would bet that
there are varying degrees of success depending on the state of the R-12
system to begin with. Obviously the results would be better with a well
functioning R-12 system that has not been opened or is otherwise
pristine inside. And pros HATE to work on systems that were converted
with the magic kits.
I did a lot of reading on this last summer when I bought equipment.
Here is the best concise source of information:
http://www.ackits.com/index.cfm?fuseaction=flush
http://www.autoacforum.com/categories.cfm?catid=20
http://www.autoacforum.com/messageview.cfm?catid=20&threadid=9172
http://www.autoacforum.com/messageview.cfm?catid=20&threadid=7931
http://www.autoacforum.com/messageview.cfm?catid=20&threadid=7927
http://www.autoacforum.com/messageview.cfm?catid=2&threadid=12769
The information I have gotten here seems to agree with everything else
I read on the Internet and the Haynes mobile A/C book I bought. They
are trying to sell stuff by hosting this forum but the information is
good and there are a lot of people in there who know what they are
doing.
John Gates
--
'85 Scirocco
'97 Jetta GLX
-----Original Message-----
From: Timbo <timjmcconnell@gmail.com>
To: haygood@myway.com
Cc: scirocco-l@scirocco.org
Sent: Sun, 19 Jun 2005 09:41:02 -0600
Subject: Re: Any one know anything about A/C?
The interesting thing about this system? NO sensors at all! All it has
is a temperature sensor on the evap for the thermostat. That's it. The
other wires are 3 for fan speed, one to turn the system on, and the
power and ground!
The A/C was just serviced in 2001 I think - with R12. So I didn't
bother with o-rings.
--Timbo
On 6/19/05, Brian Haygood <haygood@myway.com> wrote:
>
> Yeah, what he said. I did the R-134a thing a couple of years ago. I
had an
empty system to start with. Got the conversion kit from Wal-Mart for
$33.XX. I
didn't replace the drier or any O-rings and assumed I would have leaks.
Two
years later it blows cold. It's probably a shade less effective than
R-12, if I
had to guess, but not bad.
>
>
>
> If you get the compressor to spin, don't spin it dry for more than a
second or
two. There is a low-pressure switch that doesn't let the A/C compressor
turn on
with no pressure. It is one of the two switches in the A/C line at the
passenger end of the A/C condensor (the thing in front of the radiator
:O).
Your's may be located elsewhere b/c of the dealer install. If your 12v
to the
wire on the compressor works out, then bypass that pressure switch
(jump it),
and see if you can turn the compressor on from inside the car.
>
>
>
> BH
>
>
>
>
>
>
>
> --- On Sat 06/18, Foxx (in a box) < foxxinabox@wideopenwest.com >
wrote:
>
> From: Foxx (in a box) [mailto: foxxinabox@wideopenwest.com]
>
> To: scirocco-l@scirocco.org
>
> Date: Sat, 18 Jun 2005 20:52:30 -0400
>
> Subject: Re: Any one know anything about A/C?
>
>
>
> > Specificly - I think there is enough there of my dealer installed
a/c<br>>
to make it work. It needs to be recharged - so there's no pressure.
Is<br>>
there a way to make the clutch of the compressor snap on to test
it?<br>>
(there's no belt on right now)<br>> <br>> Also - Will I regret going
rf134a?
anyone got some r12?<br><br> i would think that you might damage your
compressor clutch. reason <br>being is that you add oil to the system
when you
convert/recharge. if <br>there is no pressure to your clutch you might
experience a no oil issue. <br>there is a switch in the line that will
prevent
your clutch from <br>engaging if it senses low pressure.<br> as for
r134a,
i've had no problems. i converted my old '86 and my <br>dad's '84
rabbit with no
ill effects. still blows quite cold. if you can <br>find r12, good
luck. most
places won't sell it without a license and if <br>you do find it, it's
bound to
be expensive. that said, it is out there <br>but it's just finding it
> that's the pain.<br><br>-- <br> /\_/\ Foxx (in a box)<br>< o o >
http://foxx.tripod.com<br> \ /<br>
?<br><br>_______________________________________________<br>Scirocco-l
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>
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--
Early 84 Scirocco 8v Alpine White
Early 84 Scirocco 8v Pewter Metallic
Early 84 Scirocco 8v Plain ol Black
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