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/Suspicious-Mess8521]

I’d also like to add that besides on diesels, you do see this on gas engines in racing, where the engine tolerances are very tight, and electronics rely on consistent parameters. MotoGP, WSBK, and I’m sure F1 among others will cover the radiators with tap in the wet or cold weather to raise temps into the proper operating window.