Peter Krogh wrote:

Peter, I believe that all thermostats allow for a small amount of coolant to pass
through even though the engine is cold and it is in a closed mode. Some
thermostats, not on Vanagons, have a small bleed hole to allow coolant passage. I
simply don't remember about the Vanagon, but I'll be it allows it to happen in
some manner, otherwise the pressure head against which the coolant pump was
pumping would be enormous. I know on my 88 GL there is a plumbing loop installed
that circulates coolant around the engine, especially the heads, even when the
thermostat is closed. I believe this prevents hot spots while the engine is
warming up before the thermostat opens. I had an 85 GL with the 1.9L but it's
been a while and I don't remember the configuragitn. Perhaps the Bentley could
help here.

One other thing. If I remember correctly, sometime in the past there was a
discussion about some thermostats not fitting properly and causing heating
problems. This is certainly worth pursuing in the archives. Maybe some other
listmembers remembers more of the particulars and can fill you in.

Good luck,

John Rodgers
88 GL Driver