everyone, thank you very much.

  With these helpful posts, I'm set to start finding and fixing the
problem.  My plan of attack, forming now, is to first close off the rear
heater circulation and re-fill/re-bleed the cooling system to make certain
the bubbles coming into the pressure reservoir are actually combustion
gasses. I have smelled very faint coolant smell when I first start up the
rear heater.
 I'll try the air into the spark plug holes trick, too.  I did that the
other way when I had a leaky headgasket two years ago....Pressurized the
tank with the plugs out and heard and saw the coolant hissing in to two of
my cylinders...
  Then I'll pop off the head and see.  I've been anticipating this motor
having problems, actually expected it sooner..it's done well for an 18yr old
motor of unknown use and maintence.   I've been putting a lot of hard miles
on it...It's my only viable transport right now..well...+was+ till
yesterday...
 I'll also probably call my nearby parts yard this morning and just see if
he still has some those used inline motors available and what he wants for
one of 'em now.  I may be better off  ($) to just run into Portland in my
wife's hand-me down Subaru Forester and pick up a "new" motor.
  Thanks again, I'll post what I find soon.

  Don Hanson

On Mon, Apr 26, 2010 at 3:11 AM, Dennis Haynes <d23haynes57@hotmail.com>wrote:

> Compression testing will not detect a small combustion chamber leak into
> the
> cooling system.
>
> Dennis
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: cooling system diagnostic help? Long, lots of info about whats
> been done so far.
>
>  At  4/25/2010 08:31 PM, Karl Wolz wrote:
> >Don,
> >
> >I'm with Mark on this one.  If you have a friendly mechanic, he can use a
> >"sniffer" to detect the presence of exhaust gasses in your pressure tank -
> a
> >pretty sure confirmation of our diagnosis.
> >
> >Karl Wolz
>
>
>
> Compression testers are cheap....
>
>
>
> Rob
> becida@comcast.net
>