Try a new cap on the expansion tank (not the overflow tank).  I just had a
similar problem on my '85.  Every time I came to a stop, water would come
out of the overflow.  Switched the cap and the problem disappeared.

Good Luck,

Jeff

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM]On Behalf
Of MICHAEL POPE
Sent: Thursday, May 29, 2003 3:47 PM
To: vanagon@GERRY.VANAGON.COM
Subject: coolant issues / head gasket?

Hey now,
I am the proud new owner of a 89 Westy, Rosebud as we have named her. anyway
we are having confusing cooling issues. 1st of all the person that sold her
to me thought that a head gasket was bad (so we got a good deal) rebuilt
engine 20,000mi-she is not leaking any fluid anywhere! so when you drive her
on the freeway or up a mtn.aty a good rate of speed the refill tank(behind
the license plate) starts to fill to the point of overflow!-this has only
happened once as I keep a really good eye on the gauge-as it climbs I let
off the gas and get where I can pull over-making sure I don't overheat.,
really only seems to happen under load and not all the time- so I took her
to trusted mechs, thjey drove her for 2 days- no troubles - so far we have
driven her 1200 miles -overflowed twice- not quite ready to take heads off
yet-sometimes coolant level remains same level overnite sometimes refill
tank goes into overflow tank after she cools all the way down-once again no
consistency  with issues- going on family vacation in 2 weeks so trying to
get bugs ironed out..please help
Michael