How cold will it start

you just wont know until you get to the point it just doesn't start
good batteries and good compression it should be fine
if it has been rebuilt already no reason for it to not start
a million miles on an 06 without a rebuild might be dicey

 

If your parked where you can get help I'd take my chances. If your out in the middle of nowhere I'd idle.

 

Keep a can of Either. when its cold 5 degrees F with Non Synthetic 15w-40 I know my truck well enough that the first 15 or 20 cranks are going to be the strongest, so i usually spray a 3 second shot of either in the breather and then turn it over until it starts. But i hardly ever have to do that.

 

If you've got a place to plug it in, you could. I'd run it, myself. No-start service calls suck. I only shut the truck off below 15 at my house, where I can park out of the wind and plug it in.

 

i have shut my truck off while i was with friends in ND. was gone for day and a half. it started at -1. it didnt like it but it did start. i have just over 345k on it

 

did it start?

 

it did,, just sounded really sick. after a few min it sounded nomral. personally i would never shut the truck off below 10F

 

Why not run it for an hour, shut it down for 3 then run it another hour and so on?

Don't forget to pack your jumper cables. Then you can watch all the nice drivers look at you holding your cables up in the air while they zoom past you in the truckstop!