Does ULSD have any harmful side effects on an engine?
No harmful effects are expected for diesel engines as a result of moving to ULSD fuel. However concerns about diesel engines using ULSD fuel may have been raised in the past with regard to lubricity and seals. These topics are addressed below. Lubricity Some diesel fuel pumps and injectors are lubricated by the diesel alone. The process of removing the sulphur from the diesel reduces the fuel’s lubricant effect. In order to restore the fuel’s lubricant effect a lubricity additive is added to the fuel. This additive will also help to protect the fuel pumps and fuel injection systems. Seals With some older diesel vehicles, fuel pump seal leakage did occur in some countries when they switched from high sulphur diesel to low sulphur diesel. This effect was actually due to a substantial change in aromatic content (in this case the reduction accompanying the reduction in sulphur) in combination with “aged” seals. The experience in other parts of the world to date has shown that these problem
