Diesel fuel changes in manufacturing

Has diesel fuel changed since the beginning of 2007? I have heard that some ingredient has been removed and now you need an additive added to each tank fill.

Sulfer has been removed…and there is NO additive you need to add. Removing sulfer is a good thing.

Since October 2006 U.S. road diesel fuel has be required to have less than 15 PPM sulfur content, this is called ultra low sulfur diesel (ULSD). Previously the limit was 500 PPM (LSD). This change has required additional processing of the fuel and has resulted in some concerns over lubricity (although it still must meet the ASTM D450 specifications), shrinkage of seals in older engines, and a slight reduction in energy content (1-2%) depending on the process used to reduce the sulfur content.

As expected, there are lots of snake oil salesmen trying to tell everyone the need additional additives. In my experience, you don’t need to do anything differently to run ULSD. The advantage of this fuel (similar to the euro diesel standard) is that it allows the use of state of the art pollution controls on diesel engines, these engines could not withstand the use of LSD.

Two things have happened. One happens every year, that is they adjust it for cold weather.

The second thing was a one time deal. They upgraded the fuel to ULSD by removing sulfur so we can have much cleaner running engines and more advanced engine designs that most of the rest of the world has had for years.

Sulfur does have a lubricating quality to it. Some people have feared that the change would result in more wear. So far that has not been observed. The manufacturers add additional lubricants to provide the needed replacement. There has been some evidence that the new fuels are resulting in fewer problems overall.

Actually, the sulfur does not have the lubricating quality, but a separate consequence of the process that removes the sulfur is a reduction in the lubricity of the fuel. As a result additives are requred to bring the fuel back within specifications, no additional additives should be required. Just a nit.

Correct. Another way of stating it is that removal of sulfur also removes the part of diesel fuel that was lubricating injection pumps and injectors. It’s good to hear someone say that fuel vendors are doing a consistent job of replacing this vital lubricant. I was not confident at the beginning of ULSD that this would be done reliably so I have been adding and will continue to add one quart of B100 biodiesel to 12 gallons of ULSD for an indefinite period of time. Biodiesel has excellent lubricity for injection pumps and injectors and at the low concentration used, has not affected my older diesel’s fuel system components.

I certainly can’t guarantee that all fuel vendors are meeting the spec, but I sure hope they are. I’ve put about 50K miles on ULSD on my old diesel.