At the Escapees Heavy Duty Truck Rally held at Doonan's Kenworth in Wichita, KS earlier this month, we were briefed by a fuels expert. There were many questions about ULSD and additives. The bottom line was that some engines are having problems, partly because of the newly mandated emissions and partly because of the ULSD needed to meet those emmissions. The new Cats seemed to be having more than their share of problems.
The changes to ULSD have caused several problems with all types of older engines. Occasionally, fuel system seals can break down and leak when changing from LSD to ULSD (especially w/biodiesel). Dirt and contaminants in the fuel tanks and fuel system tend to break loose and plug fuel filters - again an occasional occurrence.
One consensus was that some additive may be appropriate. There is a thread on the Escapees hdt forum that links to a list of additives and their cost/effectiveness. Some of the "old standards" are not necessarily the best for ULSD issues.
Another consensus was that biodiesel blend (up to 20%) was as good as any of the additives for lubricity issues; however, the biodiesel tended to break loose contaminants in the fuel system too. Most if not all of the hdt forum members carry several spare fuel filter, because of the risk of the potential problems mentioned above.
2003 Newmar Mountain Aire 38RLRK
2001 Volvo VNL42T420, ISX, 181"wb, 3.42 axle, super 10, gearmaster