>>Plugging in is mandatory for the diesel along with synthetic oil.
Do you use the Shell Rotella T6? I know a bunch of guys who use that in high performance Euro car engines. Sure beats buying M1 0W40 Euro car formula, or the equivalent Castrol product. Wal-Mart carries the gallon jugs of the T6, not of the 0W40, at least around here.
I use the Rotella T6 5-40 synthetic in my dually year round though in the winter I replace one quart with Amsoil 0-20 and I add a half pint of Marvel Mystery Oil.
All three of my water cooled motorcycles use Rotella T6 5-40.
But in my wifes SUV I use 5-30 Amsoil year round, my oil change never exceeds 2000 miles on my Silverado 8.1. Hers will go up to 3000, I simply do not trust any oil past 3000 miles. Bob is the Oil Guy has done many a test on the Rotella T6, awesome performance for the price.