Just talked to a guy last night that has a 01 7.3 with 125k and he says he has to plug his up under 45 degrees for about two hours before crank. Mine is also a 7.3 with 235k and I haven't had to plug mine up yet I also have a heavy duty starter is that normal to be able to crank it without plugging it in?

 

I don't plug mine in unless it gets down below 20 degrees, and I'm going somewhere early in the morning. I always let it warm up before I put it in gear and drive it as well.

 

yeah i atleast let mine warm up for 10 minutes. I heard a while back, in a 8hrs a diesel uses a half a gallon at idle but could be a myth