I am having similar issue with a 90 van I have....and i have tested for
combustion gasses, replaced both expansion and overflow
tank..........................and radiator.  Blows my mind.

Adam P
Charleston,SC     Coburn, WV
81  Westy "The Brick "
70 Single Cab "Whitey"
74 Beetle "Ol Yeller"
73 Transporter (STILL at paint shop)
1988 Vanagon Wolfsburg
1976 Transporter (New CA bus)
1974 412 "Goldmember"
Used Vanagon Parts for sale (mostly aircooled)
----- Original Message -----
From: "lauterba" <lauterba@BELLSOUTH.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Saturday, October 04, 2003 10:08 AM
Subject: Re: water pump

> Doubt if air is being pulled in from the water pump.  Suggest that you may
> have a pin-hole leak somewhere that will let air in but not coolant out or
> coolant out where you can see it.
>
> John Lauterbach
> Macon, GA
> '84 7-passenger
> ----- Original Message -----
> From: "Jim Morgan" <JM060356@AOL.COM>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Friday, October 03, 2003 7:39 PM
> Subject: water pump
>
>
> > Good evening Volks,
> > I would like to pose a question to the collective wisdom of the list.
> > Could a water pump draw air into the system? I have been fighting air in
> the
> > system for little over a year. Not much,about 10 seconds of air out of
the
> > bleeder, rising
> > over flow tank. I am paranoid and i check every week after reading posts
> on
> > the list. I know that it is a good chance that I am getting combustion
> gases
> > in(208,000. on the clock)
> > but can the pump be adding to the mystery. I have done compression tests
> > (125-140)
> >  and no change seen on the leak down .
> >
> >
> > Jim Morgan 86GL
> > "Breadbox" 208,000.0 automatic
> > Westlake,Ohio
> >
>