Grill-blocking mpg testimonial

I've been reading the various grill-blocking threads, but hadn't decided to take the plunge until the temperatures around here dropped to minus 10 degrees. So last week I cut and installed 5/8" black pipe insulation for a 100% block at these temperatures. The Result: WOW!

The cabin now heats up much more quickly, and my average gas mileage, which had been in the 42 to 45mpg range, has increased to low 50s. I actually had a 100 mile trip that showed 60 mpg on the HSI--summer time mileage at 20 degrees.

Of course, I am concerned about the temperature of engine components with the grill blocked. Question for the grill-blocking experts: I believe that the outside temp sensor is near the bottom of the radiator. If I could move the outside temp sensor up in the engine compartment and watched this sensor for anomalously high temperatures relative to the actual outside temperature, wouldn't this give me fair warning before the engine compartment got too hot? After all, in the summer there can be 90 degree air coming in to the engineer compartment. It is hard to believe that engine components could get too high when the outside air temperature is so cold.

Thanks all.