Some valves have a small slot that always allows some coolant to pass. If the heater really gets flow when the valve is off then time to replace it. Most times if the valve is bad it will also leak from the lever shaft. It is possible that the warm air is from what is rising up from the radiator and getting sucked into the fresh air inlet  which is above it. 

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Gregory Smith
Sent: Saturday, July 02, 2011 9:52 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Heater valve not closing?

Hey gang,

When fully closed, my heater valve still flows a little, enough to make the warmth uncomfortable as we finally head into summer here in the PNW.
 Is this by design, or does it mean the valve is faulty?  I have already checked that the valve is closing fully, adjusting the wire sheath as needed.  

Thanks,
Gregory Smith

Smith Design Studio
Small Building Company
Olympia, WA
360-239-0429
gregoryfsmith.com