Does diesel fuel contain enough lubrication for your engine?

In most cases, the answer is no.

Why does lubrication in fuel matter?

Lack of lubrication is a universal problem in the diesel world - older vehicles weren’t built to run on ultra low sulfur diesel (ULSD) and new vehicles are built with extremely tight tolerances, producing higher pressure and temperature, making the lack of lubricity possibility catastrophic. Every single diesel engine injection system relies on diesel fuel as a lubricant to protect and lubricate all the moving parts within the fuel system including injectors, in-line pumps and injection pumps. If the lubrication of the fuel isn’t good enough, the internal components begin to wear against themselves and can fail from excessive wear.

There are issues even with brand new vehicles that are supposedly designed to run on ULSD because a lot of these engines are built with parts originally designed for the European market where they have much higher standards of diesel fuel with lubricity levels that match the Engine Manufacturer’s Association recommendation of a maximum wear scar of 460 microns. Diesel fuel in the United States is held at a much lower standard meaning fuel additives are the consumers’ only way to protect your investment from:

• Excessive wear
• Premature failure
• Costly repairs

Why doesn’t fuel meet the needs of my vehicle?

The Engine Manufacturer’s Association recommends using fuel to a maximum wear scar of 460 microns in order to meet the needs of a vehicle. The EPA, however, only regulates that fuel needs to meet a lubricity ASTM standard of a maximum of 520 microns wear scar (the higher the wear scar number, the lower the lubricity). This means the fuel you are getting at the pump is only required to meet this standard and is unlikely to meet the lubricity level your vehicle requires.

The primary reason fuel at the pump isn’t up to the standard you need is because the fuel is ULSD and the EPA requires ULSD fuel for all applications on or off road. The ultra-low sulfur diesel has a 97% decrease in the amount of sulfur, only allowing diesel to contain 15ppm of sulfur. The problem with this occurs because to refine diesel to this level of sulfur, refiners must complete a process called hydrotreating.  This process removes sulfur but also eliminates some of the essential organic components of diesel that would provide lubrication to the fuel. After the diesel has been hydrotreated, refineries will treat the fuel with enough lubricity improvers to meet the 520 micron EPA standard, which does not meet the level required to prevent unnecessary wear and premature failure. 

How to improve the lubricity of fuel

Preventative maintenance is essential to keep your diesel on the road as long as possible and to prevent avoidable trips to the mechanic so consumers looking to extend the life of their vehicle’s components should be considering fuel treatments. One of the key benefits of using Archoil AR6500 Diesel Treatment is increasing lubricity to above the required standard.

In independent testing, AR6500 Diesel Treatment increased the lubricity of diesel fuel by 43%, reducing the wear scar by 267 microns. Using the industry standard ASTM D6079 test, AR6500 was tested with fuel that started off with a wear scar of 615 microns, and reduced the wear scar to 348 microns, significantly exceeding the engine manufacturer’s recommendation.

Click here to find out more about Archoil AR6500 Diesel Treatment