Curious how many people posting to this has experienced -40? Not windchill vehicles do not cool to windchill temp only cools at the rate of windchill to the non windchill temp.
Good batteries as said.
Engine should start instantly in warmer weather.
Get your glow plugs up to par.
Add a switch to burn glow plugs longer, but leave the stock timer intact. Just have to trigger the glowplug relay
Injector and pumps need to be in good shape.
No weak compression.
A good starter that spins fast, I have experienced old ones that start turning slow.
Treat starters and glowplugs as consumables.
Anti gel additive, stanadyne green, blue works also.
A good block heater is enough if everything else is up to par.
Let it warm up, pumps act kinda weird at -30 and below.
I like the idea of a webasto, instant warm heat wherever it is parked. Do they make them with a small 12v generator to run the blower?
My only experience is -35 windchill. No, it might not be like -40 ambient, but still cold enough that **** better be on point.
The webasto's that I worked on all had a timer module that would shut them off after 2 hours I think. They also had a date and time function that could turn on at a set time certain days a week. These were all school buses, so the heaters could be automatic on monday-friday mornings.
Those heaters will pulse the burner once coolant outlet temps get to 160, As said before, power draw is minimal when the glow plug is off. Even with it on I think it was less then 20 amps max draw. Even with it drawing the battery down, the starter takes way less power to crank with the engine warm, so it's still a benefit.
None of them turned on the blower, but they did turn on a coolant pump, so it wouldn't be hard to turn on the blower motor with another relay and some additional wiring. Then you'd have your automatic defrost/heat that you want. But that would be additional power drawing on the battery, so I'd be careful with it. Truthfully, it wouldn't take long to defrost windows when you already have hot coolant, and you'll get a little bit of defrost from the natural convection out of the vents.
They worked great when they worked, but make sure the fuel feed line is leak free, because they suffer from air intrusion much like the idi's, and they take forever to reprime themselves if they do leak down. I typically hot wire the pump and pulse it manually when they do because of it taking so long.
The chinese heaters are cheaper then genuine ones, but they don't include the timer module usually. If I were looking for one, I'd look at used school buses in the north.