Re: placing a cover over the radiator before starting so that engine coolant can warm up
OTR trucks have thermostatically controlled shutters behind or in the grille to accomplish the same thing. When I lived in Michigan, it was pretty common to see people who had blocked off part of the radiator on their car or pickup with a piece of cardboard to decrease airflow through the engine compartment in winter to make their heaters work better.
Your engine fan is probably a simple belt driven item, not electric nor temperature dependent like in some newer cars and pickups, so blocking part of the air moving into the radiator from the front will help it stay warmer. Remember, the thing never moves through the air fast enough to create any serious airflow through the radiator like a car does. Therefore, the fan has to move enough air to keep it cool in the hottest climates in which the tractor is likely to operate. This is way too much air in a cold midwestern winter so it depends solely on the thermostat to allow it warm up. Covering the radiator helps it out. So do the side panels on the engine area.
