I've been using a full top grille block on my Cruze Eco all winter. The lower grille is blocked by the shutter system staying closed at low temps. My engine stays nice and clean, save for the salt spray that gets through the two spots where the hood seal stops short of the edge of the headlights. I will be dealing with that.
This car has a full below engine compartment shield, though, so that has a lot to do with it. GM issued a recall to cut away part of the shield (sloppy oil changers were dripping oil on it, creating a fire hazard). Owners who have had their shield cut due to the recall have noticed their engines get much dirtier than before.
I'm keeping my shield uncut, thank you very much.
