Having grown up around truck stops and having owned MB diesel (83 sold last Dec and bought first gasser I've owned in years) to VW diesels (last was 02 model traded for the CRD) I have many years worth of diesel info to pass to the younger generation if it's desired.
Good diesel fuel in the in the US is like tryng to find a chicken with teeth.
Never buy #2 diesel from low volume source.
Don't be fooled by a sign on pump saying Premium diesel. There are five requirements for premium diesel, but only two have to be met to legally call it premium.
Never buy diesel at any place that has underground tanks. They are common water sources and if the station does oil changes they often dump used motor oil into the underground diesel tanks to save on the collection fee's for disposial, and it's not illegal in most states.
Use a good fuel additive every tank unless you are sure you are getting 50 cetane fuel or better. National average in US & Canada is 42 cetane with many companys selling fuel that's as low as 36 cetane.
If you can use a Bio diesel of B2 to B20 (B2=2% biodiesel & 98% #2 diesel and B10= 10% biodiesel & 90 #2 diesel) for best fuel and it's worth the extra money it cost in some areas. This fuel will usually be 46 to 50 cetane and you will notice a difference once it cleans out your system. This may require a filter change out if you have been running crappy fuel too long. A B10 fuel will quiten your diesel down to about the sound of some gassers at idle. (remember your diesel pumps about the half of the fuel that come to the IP (Injection Pump) back to the tank without it going into the fuel rail, so being rid of crappy fuel takes longer then you might think unless you run it to empty.
When using biofuel use a biocide on a regular basis of at least once a month to as often as every tank. Depending on things like weather to precentage of bio fuel and type used.
Diesel engines don't liked to be babied or driven like a hearse.
On a VNT turbo equipped engine do at least one max boost per tank, in the winter maybe two or the VNT will eventually have problems obtaining full boost. This can be expensive repair if not under warranty and your not a good wrench turner.
Always use a proper diesel rated oil, such as Mobil 1 0w-40, Mobil 1 Truck & SUV which is same as Mobil Delvac 1 or other full synthetic oil rate for diesel use. If using the Mobil 1 T & SUV/Delvac 1 with a synthetic oil filter such as Mobil 1 M1-211 the oil change interval can be an easy 12,000 miles. Even without the synthetic filters I have done 10k oil changes for years on diesels without any problems and I did have oil samples tested and the oil test always came back ok to run another 10,000 miles.
Looking forward to V6 MB diesel in LX cars next year for 07 models, that way I can trade the gasser Magnum for a diesel version. Love the Magnum even if it is a gasser, but with that 3L turbo diesel it would be a barn burner. This engine will also be offered in the Jeep Grand Cherokee here in the US for 07 models.
Remember in emergency when no fuel is avbailable you can pour streight VO (Veggie Oil) if temp is warm enough and drive on down the road. Been there, done that. I added 1 qt to the MB on regular basis before BioFuel was available and never a problem and it had original injectors and IP when sold and the guy that bought is is running it on home made biodiesel made from WVO (Waste Veggie Oil) that he makes in his garage for the average of 40 cents a gallon this year. He says that will drop to about 20 cents now that he has paid for the equiptment.
Real engines don't have spark plugs