Q: With fleets adopting the use of ultra-low sulfur (ULS or ULSD) diesel fuel, is there a need for additional fuel lubrication? Water cooler talk: fuel companiess dont use additives, the consumer is to install what he/she thinks. What is your viewpoint?
A: USLD will have lubricity additives added to it at minimum, to replace the lost lubricating benefits of the sulfur. This lubricant has been added at refineries, terminals etc. It would be safe to say that no additional lubricating additives would be required.
There are side effects from too much lubricity, or other additive cocktails, that can affect fuel water separators. If the proper amount is in the fuel there is no additional benefit from more lubricity additive.
If the fuel is treated properly, I would expect more wear would be attributed to the fuel filter quality, or variation in fuel quality location to location. If the user wants to add some lubricity additives it is probably ok in reasonable quantities although have no verifiable documentation of the benefit.
Also soy based bio-fuel or soy based additives is a very effective lubricant in ULSD.