Two more important factors to mention :
1 - Looking at the current temperature spectrum of surrounding regions upon the Northern Polar Cap of the Arctic Ocean, Eastern Siberia, Northern Alaska Coast, and Interior Alaska....it is all lingering -20 F to -50 F surface temperatures and migrating in a south or southeast direction - not good.
The North Pacific Ocean fronts where the warmer water is located - are not currently pushing its way north to the Alaska or Canada coast at this time, so at least for the first week of February it is going to be very cold in the Alaska Interior with local forecasts in the Fairbanks area ranging from -25 F to -45 F below temps for the next three days with wind chill temps ranging -45 F to -70 F below (I might get a day off or two because I work outside full time and it's going to be way too cold for normal outdoor tasks needed - and that I live the farthest away which is 30 miles out of the entire staff which I also have the seniority and the option to sit out when it is past -45 below)
With that said, another sound of advice I would like to mention to the OP is :
2(a) - Diesel Rigs : - Although most places in Canada and Alaska during the winter months will make sure #1 diesel fuel blend will always be available and clearly marked on the pumps, make sure you are dispensing #1 blend diesel fuel - since a diesel rig has been mentioned....
Some places will have both #1 and #2 available, other places might only have #2 available (that others will use for home heating fuel purposes) - so be alert upon which diesel blend you will potentially dispense in case a particular diesel pump is vaguely marked....
Once the outside temperature reaches past sub zero F, one will be asking for it if running #2 diesel as the fuel will potentially jell up (and will jell up in extreme cold temps) and leave one stranded which will be a world of hurt....
Probably a good idea to bring adequate spare fuel onhand as well as diesel conditioner too.
2(b) - Gasoline Rigs : Definitely carry bottles of HEET or ISO HEET gas antifreeze to keep your fuel from getting real cold and freezing up when the outside temps reach -20 F or colder (one 12 oz bottle protects up to 20 gallons of fuel effectively).
Good thing "Cardboard" was mentioned to place in front of radiator when needed....
I would add - Only cover two thirds of the radiator core space (centered)
Diesel Rigs - At (-15 F -25 C)....Gasoline Rigs - At (-25 F -35 C) or colder when traveling at highway speed.
Prolong idling is (should be) fine with cardboard in place at temps -30 F -35 C or colder...
As mentioned, if idling engine temps are higher than normal (which will typically happen in warmer cold areas such as higher elevations or a 20 to 30 degree warmer area) - REMOVE the cardboard from radiator core area.
Start being potentially cold vigilant this time of year when arriving in the central BC or Alberta areas, or if there is already extreme cold in the southern BC or Alberta area.
