The extra heater valve does nothing as long as you have a correctly
working stock valve. The stock valve can be opened or closed at will
from the front seats while under way.

Mark

Michael Diehr wrote:
> Re: hot-foot mods to avoid heat seepage through the body on hot days
>
> I've seen described:
>  * extra valve to fully shut off the front heater water
>  * pipe insulation on the coolant pipes under the van
>  * insulating material on the sheet metal downwind from the radiator
> (either inside or outside)
>    or above the automatic transmission
>
> Any advice on which is the best benefit/cost ratio?
>
>