[Piotrsko]

Since I always double heat the F250 when there's snow on the ground, I say go.for.it. turning the key off and on seems like such a waste, but my system apparently leaves them on for a bit after it starts. Current one shot system doesn't help with the start, but smooths idle enough to get to the corner without stumbling. Otoh watching the ampmeter showing 90 amps drain is a bit scary and I eat alternator output bolts. Apparently it doesn't charge with the glow plugs heating, some sort of delay programmed in. I get all the way out to the major cross street before the amp gauge goes to charge. Does give me 4 cold starts and 10 miles driving before the batteries die.

All the high altitude cold weather classified school busses I drove left them on for a while also, according to the dash light.