5.0 Fuels For Diesel M57 D30 T2 Us Engine: Notes
Diesel fuel is obtained from distilled crude oil. The distilling process is highly complicated, involving precise control of temperatures and pressures. The diesel fuel quality will vary depending on the refining process and the crude oil source.
BMW of North America LLC recommends using automotive diesel with a minimum octane rating of 51 in the E90 335D and E70 X5 3.0D. Never use other fuels such as marine fuel or heating oil, since these fuels do not have the appropriate additives or octane values. The octane number is a measure of the fuel's ignition quality, which influences both the ease of starting and combustion stability. A high octane number diesel fuel promotes spontaneous burning of the fuel, which is beneficial in a diesel engine.
The only fuel approved is Ultra-Low Sulfur highway Diesel. ULSD contains a maximum of 15 parts per million (ppm) of sulfur. Low-sulfur diesel (LSD) should never be used, because it contains a much higher concentration of sulfur (up to 500 ppm), which can damage the diesel particulate filter (DPF) as well as increase exhaust emissions.
ULSD dispensing pumps are labeled accordingly:
"B5" Biodiesel that consists of a maximum of 5% is approved for use.
The fuel filler neck has been designed with a misfueling feature that only allows the larger diameter diesel fuel filler nozzle to be inserted. The smaller diameter nozzle found on unleaded gasoline pumps cannot be inserted. Nevertheless, if any other fuel (i. e., biodiesel rated at B10 or higher, gasoline, or kerosene) has mistakenly been filled, do not start the engine, not even to move the car away from the fuel pump! Serious damage to the engine can result.
For cold weather operation, filling stations may use "winter diesel", which is an approved blend of ultra-low sulfur kerosene with ULSD. Such a blend will help prevent the diesel fuel from gelling at temperatures below approx. 20A°F. Factors which are important qualities of diesel fuel are the Cloud Point (the temperature at which wax forms in diesel fuel) and the Pour Point (the temperature at which fuel stops flowing). These qualities become very important during low temperature operation. As the temperature drops, wax can sometimes form in the fuel tank, fuel lines and/or fuel filter. If this occurs, the fuel supply lines will become clogged and resulting hard starting and rough running problems.