Standard operating procedure in cold climates.  I  can block my radiator in early October and leave it that way until May.  As noted it serves two purposes, to help  the engine run properly and increase cabin heat.  Newer cars are less apt to need this but older vehicles, especially those with mechanical cooling fans(am I dating myself here?) benefit.  Many vans in my area have the radiators blocked for winter and heater hoses wrapped with insulation, any trick you can come up with for those subzero mornings.

Mark in AK

----- Original Message -----
From: Michael Sullivan <sandwichhead@GMAIL.COM>
Date: Tuesday, January 20, 2009 4:01 pm
Subject: Re: Okay, who jinxed my thermostat?
To: vanagon@GERRY.VANAGON.COM

I've actually seen semi-trucks doing the same thing. Thought it  was to increase the heat on the core for internal comfort.
 I found that if I am low in the van, the tstat is slow to open. FYI.
>
> On Tue, Jan 20, 2009 at 6:34 PM, Mike Collum <collum@verizon.net>
> wrote:
>> >  My temporary fix was to put a sheet of cardboard (I usually  carry some under the rear cushion for something to lay under the van on) in  front of the radiator.  I covered better than 3/4 of it and, after a time, the gauge actually started to show normal temperature.
> >
> > Mike