In theory, you shouldn't have to make any changes to the cooling system from summer to winter but I believe that even with a properly functioning system, the ambient temperature effects the running temp of the engine. You can observe this by watching the temp gauge. It'll always be holding steady but runs a little low or high depending on whether it's winter or summer. I can't remember the name of this phenomenon - might be "lag" or something like that.

I don't see any harm in covering part of the radiator if your looking for a few more degrees.

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250