Thanks, Geza. I can't think of any other time when I've driven in such
cold weather, such a long downhill, and what I saw was puzzling to me.
Your experience suggests that this is normal. Reassuring.

Does anyone know where the sensor is for the dash temp gauge? Does it
report engine temperature, or that of the coolant in the radiator send or
return hoses?

--
Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
KG6RCR

On 12/1/2007 10:10 PM Geza Polony wrote:

> Mike,
>
> My '84 1.9 does exactly the same thing. I experienced this last year after
> coming down Highway 4 from Calveras Big Trees. Gauge absolutely at bottom,
> open loop mode, and--the clincher--no heat from either heater core. It's the
> long downhill stretches that get you, and no, it's not your gauge or your
> sensor. Your engine really is running cold. What the cause is I don't know.
>
> For me it was not the thermostat. When I pulled it and tested it in hot
> water, it worked perfectly, only opening at 195* or whatever it was supposed
> to. Other than that it was completely closed. This is theoretically
> impossible, at least in a conventional system.
>
> Maybe Dennis could elaborate a bit on how Vanagon thermostats are supposed
> to work in the system? I had always thought of thermostats as simple
> heat-actuated valves that closed off ALL flow to the radiator when cool.
> Apparently this is not the case in the WBX. Is there some way for coolant to
> get past the thermostat when it's closed? If not, then why doesn't the
> engine heat up the coolant?
>
> For those of you who haven't been through this, it really is a PITA.