I have read over the owner's manual several times trying to find an answer to this question to no avail, so the question is: It is bad to start the engine while the block heater is plugged in? Will it hurt anything?

Dan

It will only hurt things if you back out of the garage with it plugged in! Seriously, it doesn't hurt anything, I do it all the time. I suppose if you are going to let it idle a while before leaving, leave it plugged in until you are ready to go. It will continue to warm the thing up, since diesels warm up so slowly at idle.

Yeah, what marcdeluca said!

Here's another tip I learned from a truck driver: If you need to plug your truck in away from home, i.e. a motel while traveling, plug your truck in, then coil the excess cord up, and drive over it so that a tire sits on the coil. It really deters people from stealing your cord--not to mention guarantees a start-up in the morning!