Since I posted about difficulty starting at -6, I have researched the ULSD issue. Keep in mind my report was intended to illustrate that all other things were the same, but my CRD would not start easily in significantly warmer conditions (without the block heater) than my experience a year ago. I have reached these conclusions:
1. My fuel filter was replaced only several months ago, so I don't believe that is the cause.
2. I have used biodiesel consistently but under 20% and usually 5 to 10 %. Based on the biodiesel information available on the web, concentrations less than 20% do not impact cold start capability.
3. I found a number of references indicating that ULSD has reduced cold flow capability compared to LSD. This article captures what I read:
"Cold Weather Considerations
The refining process used to attain the sulfur ratio of ULSD affects the naturally occurring paraffins (wax) inherent in diesel fuel in such a way that can cause the fuel to gel more readily in cold temperatures.
"Though most retail fuel should be properly winterized for your local climate, some testing and experimenting with additional treatment processes will probably be in order. Higher doses of anti-gel additives may be necessary for extremely low temperatures—and not all additives that have traditionally been used for treating conventional low sulfur diesel will be compatible with—or effective—on ULSD.
"First look for packaging labels that indicate compatibility with ULSD.
Secondly, be aware that mixing conventional low sulfur kerosene with ULSD as a flow enhancer will increase the sulfur ratio and could damage emissions control equipment. And furthermore, even in cases where it is available—cutting ULSD with ultra low sulfur kerosene may be ineffective as a flow enhancer.
The winter of 2006-07 will indeed be a learning experience for diesel owners using ULSD."
Additionally, I theorize that with the recent roll out of ULSD, the annual seasonal diesel #2 adjustments and altered fuel refining/delivery in the post Katrina era, may be significantly distrupted. In fact, I read one web page stating, for example, the USLD #1 (used for seasonal blending) is in short supply.
What am I going to do about it? I am going to change my usual source of diesel supply to a retailer that has more volume with the hope that a fresher source of USLD will be properly seasonally blended. Secondly, I am going to look for some ULSD specified additives for use in December/January period when it is really cold. I can't always use the block heater!
I hope others in the cold regions will continue to report their ULSD experiences as we go through this winter.
