Nothing like bringing up and some of thread, but I'm gonna anyway since I believe it to be pertinent. It got really cold where I work, -51 and -30 ish at least for a week earlier this month. Didn't have a winter front on, no issue getting up to temp after putting some miles on. Biggest thing I noticed was terrible MPG's granted that is due to a lot of things, winter fuel, cold weather in general, 4wd usage, etc. so I decided once I went to the house I was gonna put a winter front on. Mine didn't come with the block heater cord so no winter front (bought in MT, you'd think it would be illegal to sell a diesel without a block heater cord in MT. I bought a cheap cord off amazon and it works awesome. Luckily I had 2 or 3, 2010 Ram HD winter fronts from all the cummins equipped rams I've had over the years so I made on of them work, mileage still isn't what it was pre winter fuel, but a warmer quicker, happier engine is returning right around 24-26 mpg, depending on the day!