[Christ]

I'm going to make a prediction about that right now.

It's not going to affect running/driving temperature.

I say this because, even with a grille block installed, and while driving, the air flowing under the car causes a pressure loss under the hood, and most of the heat lost from the engine while driving happens by way of this flow.

This, of course, is a theory, and may be proven wrong, but it's my guess as to what's going to happen in that aspect.

I also theorize that heat loss will take longer, although not significantly (i.e. less than 3% gain in timespan).