[Christ]

Oh, another thing that's been brought to my attention a few times:

Adding a grille block can actually INCREASE the ability of your radiator to cool your engine.

It's a rare occasion, from what I can tell, but on some cars, the grilles are placed in such a way that the pressure at the upper grille circumvents the lower grille because of the stagnation point being where it is on those models. I have yet to actually see one in the wild that I could openly point this effect out with, but I'm sure it can happen, and might be something to look into. If you happen to have one of those cars, adding a grille block would force the air through the radiator, rather than it swirling around in front of it from one grille to the other, or out underneath the radiator.

Another aeromod that is often overlooked that doesn't affect cooling in any negative way is to shroud the radiator completely, so that all the air that does hit the radiator has to go through it, rather than around it, into the engine bay.

This creates sort of a parachute effect, but the excess air has nowhere to go, so instead of going around the radiator, like it normally would, it creates a (insert proper term here) that blocks further airflow until the air that's already being pressurized in the grille/radiator area is through the fins of the radiator.

In other words, it builds pressure there, so excess air is forced around the grille, rather than allowed through it.