havent looked at a vanagon radiator but most are not a single tube
wrapping around but several tubes coming from a head and going to the
foot.  most radiators actually have more flow capability in the small
tubes than in the main ports feeding them.
BTW on a part that stated using straight coolant, dont.  two of the
leading manufacturers of coolants both point out that the density of
straight coolant is a bad load on the system and that water is needed
to properly activate the water pump lubricants in their products.
jimt
On Wednesday, Oct 2, 2002, at 00:21 America/Denver, Damon Campbell
wrote:

> you'd wan't to look more at the volume of liquid it is passing through
> it, rather than the overall size... I can't imagine a radiator the
> size of a vanagon's with coolant flowing through a single tube the
> size of a drinking straw would corroborate your conclusion of being
> overcooled.
>