Today's diesel fuel does not lubricate as it once did.
It used to be that diesel fuel users didn't have to worry about diesel fuel lubricity and how their diesel fuel would interact with injectors and fuel pumps. This was back in the day before the Clean Air Act of 1992, which led to the removal of 97 of the sulfur from diesel fuel. They might have worried about black smoke and fuel mileage, but not lubricity. But removing most of the sulfur created diesel fuel that didn't give the needed lubrication to these essential parts.
Then they compounded the problem in 2006 by moving to ultra-low sulfur diesel fuel and removing 90% of the remaining sulfur. For those keeping score, that's a drop from 5000 parts per million of sulfur in diesel fuel to just 15 parts per million, from 1992 to the present day. The hydro-treating process compromises fuel lubricity, wear rates increase in many fuel injection systems, most of which are designed to benefit from the natural lubricating properties of traditional diesel fuel. Lubricity wear problems associated with low-sulfur diesel fuels are not uncommon, and very expensive to repair.
We first have to understand why lubricity is important for diesel fuel. There are several types of diesel fuel injection systems being used by engine manufactures which depend on fuel lubricity in varying degrees. Of all systems being used, the rotary distributor injection pump is the one most dependent on lubricity because the fuel provides 100% lubrication to the internal parts of the injection pump. As the rotary distributor injection pump is highly susceptible to boundary lubrication wear (i.e., when heavy metal-to-metal contact occurs with the fuel providing little or no lubrication), this potential wear becomes more severe with increasing ambient temperature and increasing loading on the engine. Any significant wear will lead to under run and/or stalling annoyances, and eventually premature pump failure.
Both DFL and Diesel Juice are formulated with a micro lubricant called HRMT. Adding DFL or Diesel Juice to your fuel system will significantly improve the lubrication to your engines fuel system.
Protect your injectors and pumps by adding these products.