cold weather question

I wouldn't leave it running... If its just overnite you should be fine starting it in the morning... I leave my truck off for 2-3 days on hometime and it starts with no problem... WHen its below a certain temp ( not sure what it is ) or above a certain temp ( again don't know exactly what temp ) them no idle laws go out the window...

 

below 10 is where you MAY start to have issues if your truck is not set up for cold weather(apu that heats coolant, fuel treatment, etc). -10 is normally the point where you idle without even questioning it. Your fuel will gel, your filters will clog, your engine probably won't start....

also, once it's below freezing(32), be sure to drain air tanks and primary fuel filter to keep ice out of them when you shut down.

 

You will be good as long as the starting system is in good shape and the engine has good compression. Our trucks start good down to around 10f if that makes you feel better.

 

no need to keep it running

 

should be fine to shut it off in the 20's

 

Minus 33F here in Alberta today. My pickup truck, dodge ram hemi, didn't want to start for the first time in 4 years I have owned it. Got the SOB going but it took some convincing!
I have found that minus 15 is the magic number for problems to appear due to the cold. Fuel will gel up, batteries will die, air dryer will freeze up etc etc. if you have an engine coolant heater ( webasto or espar) then set the timer for 2 hours before you want to start up in the morning, that will help get the engine turned over a lot easier in the cold. Also as others mentioned , drain your air tanks ( if you get problems then take the main line off the compressor and add a small amount of air line antifreeze) also add fuel conditioner (Howes works fine and is available at most truck stops) keep some spare fuel filters and a filter strap wrench to change them out if needed. In my experience if your fuel gels but you can get the truck to run then get it to the fuel island and add some hot fuel from the pump, this has worked for me in the past to help thin the fuel back out.

 

Why not plug the block heater in? Most hotels will allow you to do this and some will load you a cord if needed. The block heater will keep the engine up to 80+ degrees.