Agree, the distributor will move to winter grade diesel fuel. I have used and sold winter grade diesel, and have run test engines on it for certification purposes. My point was that the winter grade diesel that we get does not necessarily have the same properties as summer diesel. It is often thinner, it has less energy (heat content), and it is not as oily (technically, it has less lubricity). It depends on how the distributor is blending the winter fuel.

With less heat content your mileage will suffer, often significantly. That is because you are purchasing your fuel by volume, not energy content. The lubricity can be compensated for with additives by the fuel distributor. The question was whether those additives provide sufficient lubricity for the high tech injectors used on modern BMW diesels. I would love to hear that there have been no problems with BMW diesels in extreme cold. I have just had lots of service experience with other diesels in extreme cold (Yukon, NWT, Nunavut, Northern BC and Northern Alberta).

I finally found information on diesel heat in the X5 35d.

For the US market, the 35d will receive supplementary heat when the engine is too cold to provide heat to the heater core. BMW says ... "The supplementary heat will come from an electrically activated ceramic heater in the heater box which will be powered by excess capacity in the alternator"

You got there before me. This device, known as a PTC heater, is currently standard on all European spec Diesel BMWs. It doesn't start until the engine has been started. In Europe, an additional diesel burning heater, which can be set to pre-heat the coolant and the interior is a factory option in the cold climate countries. For some reason, in the UK, the X5 and X6 seem to be the only BMWs we can have a diesel burning heater on, we can't get it on 3s, 5s etc.

Stewart.

While it would be nice to have warm engine and car when you come out of your office at the end of the day, knowing that you can get instant heat from the ceramic heater puts you in a better position than if you were driving a gas engine vehicle that may take 10 minutes to start warming up.

On the other hand, I'll be wanting to see if the diesel engine can produce enough engine heat to keep itself at normal operating temperatures during very cold temperatures. This is important as you don't want to have to be relying on electric heat for all of the heating needs; it will tax the alternator and as the component is belt driven, will increase fuel consumption.

I raise the point because of my experience with my 2004 Dodge diesel pickup. When it wasn't hauling a load, it would take 30 minutes to reach operating temperature when the outside temps were -20C and colder. One winter, we suffered through a week of daytime highs that did not rise abouve -33C (don't ask about the nights). During this period, the engine temperature guage needle didn't move past the first mark on the guage. When I was at a stop for 15 minutes and idling (long train), the temperature guage actualy dropped back to the cold line. It was a miserable week, to say the least.

I'l be waiting until the winter weather sets in to test the X5's heater. :)

Off topic
 

One winter, I spent 30 days when the temperature never got above -40 C (which purely by coincidence is the same as -40 F). Dropped to -46 C several days and nights. With full winter fronts (covering the radiators) the Ford trucks we used wouldn't warm up. We needed belly tarps in some cases, as there was too much airflow around the engines, ie covering the grills wasn't enough. Didn't matter if they were diesel or gasoline, and it was worse at idle or with no load.

The real problem was that the Explorers had the steering racks down low, away from the engine heat. The fluid in the racks went solid after a period of time in the straight ahead position (like driving down the highway), so as you drove, every now and then it would be as if the steering column lock was stopping the steering wheel from turning. Lots of fun.

Just picked up a 35d last week and it's been about +10 F for the last 3 mornings. The heated seats and steering wheel help while the heater warms up very quickly. I wish I had this 35d the past winter!

I test drove a X5 35d a few weeks ago. It was -20C and the vehicle had been outside for 2 days without being started. I would say it warmmed up inside at least as quickly as a gas model.