I've been looking at 300Ds but I have concerns about their ability to start in the Winter. When did Mercedes begin making diesels which had no trouble in Winter starting and were considered good cars?
Hi Alchan, you can do a "search" to find all kinds of good stuff on winter fuel.
#2 diesel will give you better performance and economy than #1. This is because it naturally has a higher heating value than #1. The heating value (not cetane) is what produces power.
But as temperatures drop (around 20 to 25F) #2 diesel begins to gel and can not flow through your engine's fuel system. On the other hand #1 will flow well below zero. Your -10 to-15F temps are no problem for a winter #1 fuel.
So it is a trade-off. You can't have both a true cold weather fuel and a best performing fuel.
But there are a couple of best options, depending on what your fuel suppliers do. Some fuel suppliers add an anti-gelling additive to #2 fuel to maximize performance and cold-weather abilities. Other suppliers blend #2 and #1 fuels based on expected ambient temperatures. Usually these two types of winter fuel are found where climates are moderately cold. In extreme cold climates you will find straight #1 or possibly a straight #1 with further anti-gel additives (arctic fuel). IMO running straight #1 in your area is a bit extreme and unnecessary and adding futher anti-gels to that is rediculous.
Since blending #2 and #1 fuel results in a drop of heating value (power), many prefer to run #2 with an anti-gel additive. But this can be taking a chance if temps drop further than the additive was calculated for.
The best advice is to talk to your fuel supplier, not the gas station attendents. Optimally you want the highest heating value with the best anti-gel capabilities. At -10 to -20F I would suggest a good winter blended fuel. Carry a bottle of anti-gel behind the seat to add if the temps dip below -30 or -40F.
FYI, "premium" fuels can mean anything from increased cetane, to a special formulation of additives and detergents. It doesn't always mean more power or better gelling characteristics. And all fuel, either #1 or #2 meet the minimum cetane and sulfer regulations.