Mobil Diesel Efficient FAQ

Curious to learn more about Mobil Diesel Efficient?  Here are the common questions we have received about this product.  If you have additional questions, please reach out to us.

What is Mobil Diesel Efficient (MDE) fuel?

• MDE, delivered by ExxonMobil authorized resellers, is the first and only fully formulated, additized diesel fuel with a proven fuel economy claim in the United States.

• It is specially engineered to help improve fuel economy and boost engine performance by cleaning up injector deposits. This new fuel also helps improve power, increase engine responsiveness, and reduce emissions. MDE fuel can also help guard against internal injector sticking which can contribute to premature injector failure. Furthermore, MDE fuel offers excellent fuel system corrosion protection and can help prevent premature fuel filter plugging.

I already use an additive and manage the inventory and dosing procedures in-house. What would be the benefit of using MDE fuel instead?

• MDE fuel is a fully-formulated fuel, meaning the additive is injected and blended into ASTM D975 base fuel with precision at the fuel terminal.
– Correct additive concentration and adequate blending are essential to harnessing the benefits of fuel detergents.
– Hand-dosing additive requires administrative and operational costs to research, purchase, store and dose additive.
– Under-dosing could result in lost performance, overdosing could result in adverse impacts to your equipment.• MDE fuel delivers guaranteed quality and proven performance without requiring any extra effort on the part of the customer.

Why would I need to use an advanced diesel fuel such as MDE fuel today?

• Modern diesel engines have very sophisticated fuel systems engineered to meet today’s stringent diesel engine emissions requirements. MDE fuel helps prevent deposit formation and cleans up the existing deposits that may be negatively affecting your engine performance. Deposits on the injector needle guide or control valve, which have extremely tight tolerances (~ 2 – 5 microns), can jam the needle movement and cause early failure of the injectors. Deposits that build up inside and around the injector nozzle can restrict fuel flow and deteriorate the fuel spray quality which results in loss of engine power, increased emissions, and reduced fuel economy.

What additive types are contained in MDE?

• MDE fuel’s patented additive technology is a multifunctional detergent system that cleans up and prevents the formation of both internal and external injector deposits. Cleaner injectors lead to improved performance. The size of the benefit is dependent on the type and amount of accumulated deposits, type of fuel system in use, duty cycle, and other factors.
• It also contains a demulsifying agent to shed water.
• In northern regions of the US during cold weather months, the MDE fuel additive system also contains a compatible cold weather additive to enhance low-temperature operation. (Note: MDE fuel is added to ASTM D975 base fuel, which may contain other components in order to meet the required specification targets (i.e. cetane improver, lubricity improver).)

How is MDE fuel different from standard diesel fuels?

• MDE fuel is treated with a patented additive package that is specially designed to clean up and keep clean both internal injector deposits and nozzle deposits. Research demonstrates that MDE fuel can help improve the performance of your diesel engine.

Once I start using MDE fuel in my equipment, how long will it take to see results?

• MDE fuel will start working right away to clean up fuel system deposits and noticeable benefits resulting from the cleanup process will vary depending on multiple factors such as equipment duty cycle and the starting condition of the fuel system.

• The level of improved engine performance depends directly on the level of performance degradation that has taken place as a result of fuel system deposit accumulation.

• Customers have reported experiencing an improvement in performance after three to four tank fills of MDE fuel.

When I convert to MDE fuel, will I need to change my fuel filters more frequently?

• The first two to three tank fills may result in a more frequent fuel filter replacement interval. This is due to MDE fuel “cleaning up” the fuel system. After the initial “clean-up” process, the service intervals will return to historical levels.

• MDE fuel can protect filters from premature plugging by saturated monoglycerides, which are introduced with biodiesel and are the lead cause of premature filter blocking.

• MDE fuel can also improve fuel thermal stability and help prevent premature filter plugging caused by thermally stressed fuel.

Does the Mobil Diesel Efficient meet ASTM D975 specifications?

• Yes, MDE fuel is an ASTM D975 compliant fuel.

• MDE fuel technology is blended into ASTM D975 base fuel at designated fuel terminals and does not affect ASTM D975 compliance. What types of applications and engines would benefit from using MDE fuel?

• MDE fuel is designed to provide benefits in all types of applications requiring an ASTM D975 fuel including but not necessarily limited to light-duty passenger cars and trucks, on-highway commercial trucks, and off-road construction and mining equipment.

Does the Mobil Diesel Efficient meet ASTM D975 specifications?

• Yes, MDE fuel is an ASTM D975 compliant fuel.

• MDE fuel technology is blended into ASTM D975 base fuel at designated fuel terminals and does not affect ASTM D975 compliance.

Will it harm my equipment?

• No, a rigorous test program was performed on MDE fuel to ensure that no adverse effects will result from its use in vehicles specifying the use of D975 diesel fuel.

Is MDE fuel compatible with biodiesel blends?

• Yes, the performance testing was successfully performed using a B5 base fuel.*

• MDE fuel is available in biodiesel blends up to B5 where B5 is available, and up to a B11 in Illinois.

Note: Drivers must consult their OEM service manuals to determine the biodiesel content approved for use in their specific vehicle.

How does MDE fuel compare to “off-the-shelf additive in a bottle”?

• MDE fuel carries the benefit of being homogenized at the terminal, requiring no additional mixing upon receipt and guaranteeing accurate additive concentration to yield desired engine performance.


Interested in beginning your Mobil Diesel Efficient journey? Contact us today and find out is MDE is right for your fleet.