I installed a new alternator in my 85 GL last month and it seems that a side
benefit (maybe coincidental) is that after consistently getting 16.5-17 mpg
before, and this is driving in a mix of Atlanta traffic with the AC running
most of the time, I am now getting in the 19-20 mpg range.  One of my fill
ups resulted in 20.5 mpg!  About half of this tank was used driving back
from Auburn on the the freeway, though.  Running the Vanagon AC has never
seemed to diminish my gas mileage, by the way.

Donald Baxter
Atlanta