There are also test strips you can use for the same thing.

Tom
www.towercooler.com

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf Of
Karl Wolz
Sent: Sunday, April 25, 2010 10:32 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: cooling system diagnostic help? Long, lots of info about whats
been done so far.

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