Date: Wed, 25 Jul 2001 15:28:16 -0500
Reply-To: Larry Alofs <lalofs@ENTERACT.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Larry Alofs <lalofs@ENTERACT.COM>
Subject: Re: AC Conv: R12 to R134A, long, Larry A.
Content-Type: text/plain; charset=us-ascii
Sorry, I don't remember where I got that adapter. I spent about a year and a
half gathering parts and shopping around while I read the posts on
aircondition.com and on this list and generally stalled around. I got adapters
at various places around Chicago: Pep Boys, Trak, Auto Zone, NAPA, K-Mart,
maybe others too, planning to convert my van and my daughter's Saab.
Finally SWMBO issued an ultimatum and I did the van about 3 weeks ago. Got
the receiver/dryer from Ken, O-rings to fit those connections from Pep Boys
(generic set of blue rings, three or four each of four sizes), O-rings for the
compressor connections from the dealer, a can of ester oil, some purple leak
detector dye, lots of R-134A.
Disconnected and dismounted the compressor to empty out the old oil, but only
got about a teaspoonful. I assume a lot of the oil leaked out with the R-12 as
reported by the PO. Put about 4 oz of ester oil in the compressor.
Installed the new receiver drier. Gave it about 1 oz of oil. Put on the
adapters. Borrowed a vacuum pump from my place of employment. Had to
improvise a way to connect it to the center hose of my 134A AC gauge set since
I didn't have anything around with ACME threads. I let it pump for about 3
hours and then shut it off for about 30 min while I watched the vacuum on the
gauge to be sure that there weren't any really gross leaks.
When I was ready to add the refrigerant I discovered that the hose from my
gauge set wouldn't attach directly to the R-134a cans. Back to FLAPS for a
tapper valve. Since the compressor may not come on at all with no pressure in
the system, I put most of a can in the low side before starting the engine,
etc. Setting the can of refrigerant in hot water helps to encourage it to
leave the can and go where you want it. After starting the car I continued
adding refrigerant and the pressures came up as expected. Since the original
R-12 charge was supposed to 51 oz and they say that with 134a you should use
80%, I stayed conservative and put in 3 cans total (36 oz) of 134a. By that
time, if I recall the low side pressure was around 30 psi and the high side was
about 220. The high pressure switch was kicking the radiator up to a higher
speed periodically (as per Bentley) as soon as the high side got to about 200.
Once I closed the engine compartment so that it wasn't sucking in such hot
air, it started to work fairly well. I took it for a short drive and stopped
in a parking lot to check with a thermometer. With the temp control at max
cold and the fan on 3, I got about 52 F and with the fan on 2 got about 48 F.
This is measuring at the opening of the rear housing around the evaporator. (My
"tunnel" fell down suddenly about 6 months ago. I'm not sure if I'll try to
put it back up. Not banging my head any more!)
In the past 3 weeks we have driven it from Chicago to northern Pa and also
into Indiana and Mich and the AC seems to continue to work fine, producing
about the same temps. If it eventually leaks down, I'll put in the leak
detector and go from there. At least 134a is relatively cheap.
I recently saw that Interdynamics has a charging kit on the shelves now
which includes a tapper valve, hose, and a low side pressure gauge which has
colored zones to indicate the proper pressure for 134a. This might be a
reasonable compromise if you don't want to invest in a full gauge set, but want
some feedback. There is probably no great need to connect to the high side, so
you could probably skip that adapter.
Keep the cans right side up to dispense gas not liquid, and add only to the
low side (near the compressor, large diameter hose).
good luck.
Larry A. (cool and comfortable)
Michael Townsend wrote:
> Thanks for the advice. I did find the expnsion valve and ordered one. My
> van is a 90 Carat (non-westy) so mine will probably be the same as yours.
> I will attempt to remove the plastic housing to get to the expansion valve.
> I need to clean the condensation pan and drains anyway. Thanks for the
> warning of the clearance from the trim panel. I'll check to see if my
> conversion kit had the short one. Since you add the R-134 to the low side
> near the input of the compressor, why do you need access to the high side
> anyway? Where do you get the cheap coreless adapter?
>
> Thanks,
> Michael Townsend
>
> ----------
> > From: Larry Alofs <lalofs@enteract.com>
> > To: Michael Townsend <townsend@RTP.ericsson.se>;
> vanagon@GERRY.VANAGON.COM
> > Subject: Re: AC Conversion: R12 to R134A
> > Date: Wednesday, July 25, 2001 11:20 AM
> >
> > Michael Townsend wrote:
> >
> > > I'm about to do the same, but I need some more clarification:
> > >
> > > 1: Where is the expansion valve, and where do I purchase one? I
> didn't
> > > see it on our friendly internet vendors' sites.
> > > 2: I can see one of the ports on the line near the compressor. Where
> is
> > > the other one?
> >
> > I believe that Ken sells expansion valves. It is on the end of the
> evaporator
> > ( the part that cools the air). I decided that it was too much trouble
> to
> > drop it down so I didn't change the expansion valve.
> >
> > The high pressure port is behind the vertical trim panel on the left
> side.
> > (late model non-Westy) I don't know if the Westys have things arranged
> > differently.
> >
> > Don't assume that the adapters from a "kit" will be correct. There are
> two
> > different thread sizes for the original R-12 fittings: nominally 1/4 "
> and
> > 3/16 ". Of course the quick connect 134A part is different for the high
> and
> > low sides. Various permutations are possible. You may have to study
> them and
> > shop around.
> >
> > Also, in my 91 GL there was very little clearance between the original
> R-12
> > high side fitting and the trim panel. I had to use the cheap, short,
> aluminum
> > type of adapter that has no valve core of its own.
> >
> > Larry A.
> >
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