I maintain several large 2MW,16 cyl diesel generators (emergency standby) outside of Chicago. My gens need to start at any temp and be at stable speed in less than 10 seconds. Today it was -10F w/50 knot winds blowing snow into the engine cabinet. I use a 70-30 blend of D2 to D1 with anti gel (double dose) & block heaters. Coldest I've ever had to start up was -16F. No sweat starting today. I use the same mix in my Benz's. Works great. Use the block heater and keep your glow plugs in good shape. Just don't use BioD in the winter, it will gel. BTW other friends here use JP4, kero, Jet A, and other jet fuel blends in the winter in their OM617's (pretty common around airports with jets - the mechanics sump the jets during pre-flight & save up the 'juice' for their old MB diesels.