Thanks, Karl.

I was not actually serious when I posted my questions, just responding to what I
thought was a humorous thread. I am familiar with the nature of closed cooling
systems, just not with differential equations, which apparently are not necessary
anyway when discussing the Vanagon cooling system.

Guess I should have waited until Friday to post :)...

Dan

"Karl F. Bloss" wrote:

> > based on the original poster's assumption that the water pump has to work
> > relatively hard to pump coolant uphill, would it do less real work if the van
> > were constantly driven downhill?
>
> Forget differential equations.  If it's a closed non-leaking system, it doesn't
> matter how the van is facing, the waterpump is only overcoming the frictional
> losses in the system, not pumping up or down.  I.e. the more piping, the more
> friction, the more the pump has to work.
>
> Uphill and downhill don't matter because the starting and stopping point for
> the fluid is the same.  If the van is facing downhill, for every unit mass of
> coolant that's going downhill, another unit mass is going uphill and vice versa
> if it's pointing uphill.
>
> -Karl