I grew up in central IL, and it got cold there from time to time, like the time of my 21st b-day. Note to others, don't go sleep off a bar crawl in your buddy's car while they continue to party when it's -20 out.

I'd never even thought of the light bulb under the hood thing. Sounds like it could be quite effective, though. Put a 100 watt bulb on a timer and set it to light up a few hours before you need the truck, maybe? Set the bulb on a brick under the oil pan...

John B.