I don't like to do "me too" posts, but in this case I think
I can contribute a significant data point:

John Wakefield said:

>(big snip) Instead, I'll bet there are lots of water 
>cooled Vanagon and Westie owners on this list whose machines 
>couldn't perform as you described yours doing.(another big snip)

Mine does just as well as Jim's.

Probably my worst case was ascending out of Death Valley
one afternoon last August, while it was 108 degrees in 
the shade at Stovepipe Wells. Unfortunately, the road 
was not in the shade. This was on the order of a 6000 foot
climb.

We had full fuel, propane, and water tanks, two adults, one 
child, food, bedding, baggage, tools and toys for a three week 
cross-country trip, in a 1990 Syncro Westie. We must have 
been close to 6000 lbs GVW.

I did turn off the a/c during long ascents. The water temp
needle never moved completely past the little aperture for the
warning light. The radiatior fan would go to the highest speed
for brief periods while climbing in second gear, then cycle off
(or down one notch). I did turn off the a/c whenever the fan 
went to high.

As a result, I have full faith in the basic design of the 2.1 
liter wasserboxer cooling system. 

Tom F.
90 Syncro Westie