Update - I must take back my wrong backyard mechanic diagnosis of the GW
aluminum expansion tank.  Dropped the van off at the mechanics this morning
and showed them where I thought the leak was.  Of course nothing was
dripping at the time even at operating temp.  I quickly placed my finger
under the tank and was able to get a little coolant to show the mechanic.

Anyway came back to pick the van up and the tank was still in place - so?
It was actually a hose at the clamp - or so it seems.  I guess coolant was
travelling from the hose along the bottom of the tank and then dripping
down.   The hose was cut back a iittle and the van pressure and road tested
- coolant topped up  and things are all good in Vanagon land again.
Charged me for 0.6 of an hour - no parts.

So - sorry GW if tanks sales plummeted over the past 2 days or so.  I think
they are all out of stock anyway.

Bruce