Having lived up there all my life, this is what I've learned about driving in the cold up there:
- Make sure your coolant level is where it should be
- Run a 70/30 anitfreeze/water mix
- Install a 195º thermostat
- Back flush the heater core - Anchorage Radiator Service has always been good to me
- While you're there, ask if they can test the Ph level of your antifreeze
- If that doesn't work, a buddy and I installed a used Caterpillar heater in his truck. This was when I lived in Fairbanks, it was -25º F, and we literally had to roll down the windows, to keep from getting roasted out of the truck. You can just imagine the stares we got, diving down the expressway, with our arms hanging out the windows
I don't have a Cat heater myself, but I am planning on using the old heater system from my other Bronco, to add a second heater. I'll be tapping into the stock heater hoses, fit it to copper tubing, cover it with insulation, secure it to the underside of the body, up thru the rear floor, and finish it with short lengths of heater hose, to the heater in back. I will also be adding two ball valves, so I can stop all the flow back there whenever I feel like it. Plus, I can disconnect the heater in the sumer, and just cap the lines, after the valves