According to what you observed, my original diagnosis is correct. The
thermostat is not cycling off long enough to complete the defrost cycle.
You will need to either adjust the high-temp tolerance (which controls the
length of time the AC cycles off), or just replace the thermostat.

As far as the orange refrigerant, that isn't good. Has it been a few years
since you had the system serviced? It sound like it is time to have it
evacuated, and a new receiver-dryer fit. The Reciever Dryer is a filter for
the AC, and it contains desiccant to absorb moisture that pollutes the
refrigerant over time. Orange = rusting AC components, meaning the
desiccant has been saturated for a long while, and innards of your AC are
corroding.

Have a competant shop evacuate the system, replace the RD, and pull a
vacuum on the whole system for 30-60 minutes to dry everything out
completely. You may as well convert to R-134 as it is now cheaper than
dirt.

You will be amazed at how well your AC will work after this service.

G. Matthew Bulley
Bulley-Hewlett & Associates
www.bulley-hewlett.com
Cary, NC USA
888.468.4880 tollfree

-----Original Message-----
From:   John Dorn [SMTP:jrdorn@BELLSOUTH.NET]
Sent:   Saturday, June 26, 1999 4:46 PM
To:     vanagon@GERRY.VANAGON.COM
Subject:        AC Part II

Hi there,

A few days ago I asked about my evaporator freezing, wondering if it was
the switch with the capillary tube that is inserted into it.  I got some
different suggestions so today I spent a little time with it.  I checked
the evaporator fins to make sure they were clear (they were for the most
part but I cleaned them a little more), then ran the ac while right next
to the evaporator.  Almost instantly a bit of moisture formed on half of
it.  This continued to form until the moisture slowly began turning to
ice.  I could hear the switch right there cycling on and off but it is
located in the half of the evaporator that was not icing.  I took a
quick drive and I could tell that the switch was cycling on and off when
off things would begin to melt, when on they would freeze up again
(freezing a little bit more area each time), all the while the section
of the evaporator where the capillary tube goes in never even developed
moisture.

Any guesses?

Oh, I also gave a quick visual inspection of the rest of the AC
components while it was running, everything looked normal except for the
receiver/drier site glass where the color was orange (is this my
problem?).

Thanks for your help
John