New to the list, nice to see so much info. I have an 84 Westy, and the
coolant keeps coming out the overflow tank leaving the other tank bone dry,
it is not boiling over. Can a leak around the heads be presurizing the
cooling system, pushing the coolant out? Or can I have leaks in the system
itself, ie hoses or connectors and gravity and syphoning taking over? It is
especially prominant when I go up hills (I'm assuming all the coolant is
rushing towards the back and out through the overflow). I tried plugging the
line between the two tanks but that didn't work. It does have a new cap. Do
I need a special test cap for the Vanagon, or will any radiator test cap
work for  pressure testing the system ?

Thanks...Michael J. Brenner