shawkins said:
NooB question: Why do you need to cover the radiator?
So the air being pulled through the radiator doesn't cool the "coolant" faster than the engine can heat it up. If the engine can't keep up, no heat in cab, ECU thinks the truck is running cold (which it sorta is), and if cold enough, can "freeze" (think of slushy coolant) the radiator, preventing proper cooling if the engine does warm up.
This can be less of a problem with electric fans, but "most" cooling fans on trucks are engine-driven (belt driven).
Someone please correct me if I'm off base here, but this is how I've come to understand it.
Oh, and it keeps the bugs and mud out.
ON EDIT: So there is no confusion... the airflow over the radiator
does not make the air any colder, nor does it change the protection the antifreeze offers. -20 is -20 is -20, but the airflow
does make it harder for the engine to fight the cold "ambient" temps, and removes heat from "everything"
faster than still air.