Won't the system thermosiphon if the motor is shut off?

The only way to know for sure is measure the temperature at the heads in a
heat soak situation.

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Dennis Haynes
Sent: Saturday, June 16, 2012 9:09 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: when is stopping/restarting better than idling?

There are two concerns with this practice. How many cycles can the starter
take and depending on conditions the effect stopping the cooling system can
have on the engine. Especially after an extended highway run a 1-2 minute
idle down will prevent heat soak from creating a temperature spike and
stress head gaskets and stuff. Vehicles designed for this type operation use
electric water pumps to maintain some coolant flow. Audi turbos also used
water pumps and fan controls for after cooling. Some even had
injector/manifold cooling fans. To deal with this.