gascort:
hey, yeah, like Darin said, I've been on vacation
A week of camping in Yosimite, so no EM for me.
Anyway, I have done PLENTY of driving with the grille-block in really excessive heat. Heck, on my drive back from Yosimite it was +110º and driving up some seriously steep grades (read: doing nearly redline in 2nd gear) Oh, and there were two people and a weeks worth of camping gear in the car.
So that's probably the worst case senario for overheating and there was no overheating. I had the grille-opening all the way open, and the radiator fan was on quite a bit, but the temperature gauge stayed put.