In a message dated 11/17/02 7:22:13 PM, vanagon@VOLKSWAGEN.ORG writes:

<< If you turn off your heater (put it to cold) you stop the flow of water in
this pipe.  I can hardly see how this affect the cooling system of the
motor. >>

I guess I might as well have a go at adding to this mix.  In 2 vans thus far
I have noticed something which seems, at first, to go against one generally
accepted idea about Vanagon cooling systems.  Judging by keeping a watchful
eye on the temperature gauge, I have to say that a Vanagon engine runs
slightly, but perceptibly, hotter with the rear heater valve open than when
it is closed.  And that is during mostly winter as opposed to summer
operating conditions.

I reason that the mass of coolant shunted to the engine through an open rear
heater valve is being deprived of the greater heat loss it would suffer by
being routed through that big heat exchanger up front.  For all I know, it
might have been happening on all my vans before it caught my attention.  Has
anyone else noticed this subtle effect?

George