Re: frozen diesel
I use Power Service Diesel Fuel Additive. It has some anti-gelling additives. Costs about $5-7 for enough to treat 40 gallons. Pretty common in the big rig world as you'll find it at every truckstop. Plenty of below zero mornings so far this winter....no gelling problems yet.
If you're worried about fuel gelling, don't forget to check your coolant mix too. I had some coolant freeze in a small diameter line feeding my webasto coolant pre-heater on a -20F morning. Didn't freeze in the block thankfully.
'04 EB-350 6.0 PSD SMB 4x4, PH, EB-50, Aluminess F/R