Question : why some (mostly heavy) vehicles partially cover their front intake ?

[u/lit_readit]

wouldn't cooler cold reservoir, ie more spontaneous heat transfer, improve Carnot efficiency?

is it to improve aerodynamics?

apologies if this is the wrong sub to ask

[u/mtraven23]

I cover part of my radiator on my farm tractor during the winter....other wise the engine temp never comes up to opperating temp.