Date: Mon, 27 Jul 1998 07:15:04 EDT
Reply-To: GMBulley@AOL.COM
Sender: Vanagon Mailing List <Vanagon@vanagon.com>
From: GMBulley@AOL.COM
Subject: Re: A/C Freezing Up?
Content-type: text/plain; charset=US-ASCII
In a message dated 7/27/98 4:02:38 AM Eastern Daylight Time,
bpremack@WAVETECH.NET writes:
<< The a/c on my 86 Syncro GL (non-Westy) was inoperative when I purchased it
two years ago. Two weeks ago it was reborn with several hose repairs, a
new receiver dryer and an infusion of 134A refrigerant and special ester
(sp?) oil. It works great, but....
With the temp control knob on the warmest setting, the air is really cold,
and does not feel any colder if the knob is turned to a "colder" setting.
(Sorry, I have not checked it with an accurate thermometer.) After about
45-60 minutes the air gets warmer until it seems as if the a/c is no longer
operating. If the van is parked for 30-60 minutes, there is a puddle under
the right side of the rear bumper (water from the drain hose). Upon
restarting, the a/c works fine again. <<SNIPPPPP>>
What is the problem? Is it a bad temperature control
switch, a/c thermostadt or capillary tube, expansion valve, or ? The top
and side pillar housings were not removed, so the evaporator, expansion
valve, relays, etc. have not been physically examined.
<SNIP >>
Bud---
Sounds like the same problem I had on my Jetta last year. (Since VW uses
virtually identical control systems for the AC), it is most likely the same
problem you have. I'm sorry I can't be completely Vanagon specific.
The AC thermostat is stuck. Yes, you have an AC thermostat, it is there to
keep condensation from icing-over the evaporator, blocking the airflow, and
*possibly* bending the fins/cracking the coils. This is the part of the system
that cycles your compressor on and off while the AC is set to "on"
The thermostat is located right next to the evaporator, and has two wires
running to it. It consists of (on my Jetta) a 9" long, thin, sealed metal tube
(I think called an "ampule tube" ?) that connects to a 1" x 1.5" metal box
with two terminals, and two tiny hex-head adjusting screws.
On my Jetta, removing/replacing the thermostat is expensive. The part is about
$100, the labor... :(...You can get to the thermostat just fine, but on
replacement, the ampule tube has to be inserted in a very particular little
holder, just downstream of the airflow out of the evaporator. The dash has to
be removed/disassembled to accomplish this. :(
The thermostat is set (roughly), to cycle the compressor off when the ampule
is exposed to air below a certain temperature (35?) for longer than a certain
period of time (20 seconds??). The adjusting screws adjust the temperature,
and length of time the ampule will endure the temp until cycling off.
Hope this helps your mechanic,
gmbulley
cary, nc
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