[sid]

I think you could probably cover the entire top grill. It depends upon how much of the bottom grill is covered by your license plate.

My top grill has been covered for over a year now and the engine temp seems to be typically about 4 to 6 degrees cooler than before I blocked the grill. I do have only a 2.3 L engine, but I also live in Florida. I appear to be averaging about 1 mpg better around town, about 1.5 mpg highway since making this change. Of course, subtle changes in driving habits may account for part of this improvement.