For the NCV3 model sprinters, what are some best practices for cold weather driving? The reason I ask is that our van will sit in our driveway most of the winter, used occasionally. We live in Wisconsin, so temps in the -25F to 15F wouldn't be uncommon for some driving conditions.
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3) Should we take our van for a 30 minute drive on the highway to get the engine hot? Would this help avoid crud build-up from the shorter trips we will be taking?
Yes, you should regularly take your van out for a 30 minute drive at highway speeds to compensate for short-trip use in all seasons of the year (not just winter). This topic has been discussed on the NCV3 areas before as it pertains to the Diesel Particular Filter (DPF) regeneration process. Short trips may never reach the conditions to initiate regeneration, or the regeneration may be interrupted before it completes. Regeneration absence or early termination leads to the DPF getting overloaded, which leads to expensive problems.
On the other hand... I think that if the van is just sitting in the driveway, and not being used or short trips, then you don't need to take the van out regular for the 30 minutes at highway speeds exercise. You would, however, want to at a minimum disconnect the battery using the disconnect located at the driver's seat near the accelerator pedal to avoid flattening the battery due to parasitic drains when the van sits for more than a couple of weeks. Either that, or use a battery tender product to keep the battery topped off. Again, this applies in all seasons.
[Added: If you decide to use the battery disconnect, there is a waiting period after you shut off the van during which you should NOT disconnect the battery. This waiting period allows for computerized "housekeeping" activities to take place. If you don't allow them to take place, you may cause future problems with the operation of the van. I *think* it is something like 10 minutes; it should be in your manual (mine is not handy).]
Just for the winter season an additional issue of which you should be aware is the difference between normal diesel and winter diesel (assuming your van is not used frequently). Once the weather turns cold, fuel stations sell diesel with additives in it to reduce the tendency of diesel fuel to gel at lower temperatures. If you fuel up while normal diesel is being sold, and don't use up/refuel your van with winter diesel once it turns cold, then you will not have the advantage of these additives in your fuel and may encounter problems with cold weather operation. Obviously, figuring out when winter diesel starts being sold and planning your refueling to ensure your tank has winter diesel in it for the cold months will be a bit of work on your part.