I am not an expert on the symptoms you describe, but one place to start looking is
behind the plastic panel in the left rear corner. There you will find various relays,
fuses and the high pressure port. One of the fuses is a 50 amp fusible link and they
have been known to blow when you run the fans on high. Not only blow, but get so hot
as to melt the plastic block it is mounted on. Happened to me. I was able to repair it
and now never run the fan on high.
Jerry
----- Original Message -----
From: "Barry E. Muller" <bmuller@UOFT02.UTOLEDO.EDU>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Sunday, September 08, 2002 10:31 PM
Subject: Pop-hiss AC Prob

> Hi Folks,
>
> On Sunday my son and I went to the local air show for some high-speed
> entertainment.  When we left, I wanted to cool down the '91 Carat as "fast"
> as possible so opened the doors, cranked the engine up and turned the AC and
> fan on max.  About a minute later I had some unanticipated enterntainment
> when I heard a pop at the rear of the cabin and hissing sound (not unlike a
> bicycle tire going flat) for about 2 minutes.  Once I assured myself that I
> really didn't have a flat I guessed that the sound I heard was my AC system
> dumping all the 134a (yes it was converted by the PO using the kit) into the
> van.  Whatever my van was leaking smelled of rubber - not burning rubber,
> but just like air that has been in a tire (thats tyre for Clive and Andrew
> ;-) )
>
> So,
>
> A)  Amongst other things, I'm an HVAC moron, if you can, and will, help me
> with this - please feel free to break out the finger puppets.
> B)  Is there a safety relief valve in these AC systems that will go, or am I
> probably looking at a blown line, hose etc. ?
>
> TIA
>
> Barry
> 1991 Vanagon "Sauna"