Biodiesel FAQ

What Cummins engines can be used with B20 biodiesel?

The current approved engine models are as follows:

On-Highway:  ISX, ISM, ISL and ISB engines certified to EPA ’02 and later emissions standards, ISL, and ISB engines certified to Euro 3.

Off-Highway: QSX, QSM, QSL, QSC, QSB6.7, QSB4.5 and QSB3.3 engines certified to Tier 3/Stage IIIA, QSM Marine, QSM G-Drive.

High Horsepower Off-Highway built after January 1, 2008: QSK78, QSK60, QSK50, K2000E, K50, QSK45, QSK38, K1500E, K38, QST30, QSK23, QSK19 and K19.  Also Marine QSK60, QSK50, K50 QSK45, QSK38, K38 QSK19, K19. 

Cummins has approved B20 for the high horsepower engines listed above with the following fuel systems: Pressure Timed, High-Pressure Injection, Modular Common Rail Fuel Injection System and BOSCH Pump-Line-Nozzle.

What are the general fuel specification requirements?

Biodiesel must conform to the American Society of Testing Materials (ASTM) specifications.  B100 must conform to ASTM D6751 prior to blending, and the finished B20 blend must conform to ASTM D7467.

ASTM D6751 specification for B100 has been revised to now include a cold soak test.  The B100 fuel is cold soaked and filtered in order to catch impurities or incomplete reactions resulting from the production process.  As mentioned in previous communications, the stability requirement is still in effect and is a critical requirement when B100 is blended with petrodiesel to produce a B20 blend.

ASTM D7467 is a new specification which applies to biodiesel blends of B6 – B20 and includes an oxidation stability requirement.  This specification replaces Cummins’ previous Engine Manufacturers Association (EMA) B20 specification requirement.

In Europe, specifications for biodiesel are issued under EN 14214. EN 14214 is published by CEN, the European Committee for Standardization or Comite Europeen de Normalisation.

Equivalent biodiesel specifications are required internationally.

Customers are required to purchase the biodiesel blend from a BQ9000 Certified Marketer. The B100 fuel used in the blend must be sourced from a BQ9000 Accredited Producer. BQ9000 Certified Marketers and Accredited Producers can be found at

Where can I find further information as it relates to the use of biodiesel in Cummins engines?

Cummins has recently updated the Fuels Requirements – Service Bulletin 3379001.  It can be obtained on Cummins QuickServe website at Customers can also contact their local distributor and certified dealers for the bulletin.

Are there any special requirements for fuel filters?

Cummins requires the use of a StrataPore™ fuel filter media, and strongly recommends using Cummins Filtration™ filters equipped with StrataPore™ media.  If StrataPore media is not used, then an equivalent filter that meets specific performance standards must be used. For more information, please visit

Cummins also requires high horsepower marine applications to use a centrifuge filtration system to safeguard against water contamination as water intrusion is common in vessel fuel storage tanks.  Cummins recommends all commercial marine applications to use centrifuge filtration systems as well.  For more information please review the Fuel Requirements - Service Bulletin, number 3379001.

Do I need to modify any service intervals when switching from petrodiesel to B20?

Due to the solvent nature of B20, and the potential for ‘cleaning’ of the vehicle fuel tank and lines, new fuel filters must be installed when switching to B20 on used engines.  Fuel filters will need to be replaced at half the standard interval for the next two fuel filter changes. After this initial period, you may revert to the intervals specified in your O & M manual.

For EPA 2007 on-highway midrange engines only, oil sampling will be necessary for the first 6 months of operation with B20 to monitor fuel dilution of the lubricating oil.

For high horsepower engines equipped with the Eliminator™ oil filter option, oil sampling will be needed to determine the appropriate oil change interval.  Oil samples should be taken every 250 hours of operation and analyzed according to the Cummins Engine Oil Recommendations Bulletin 3810340 which can be found on or through local distributors and certified dealers.  This process should be repeated for at least three oil change intervals to ensure consistent oil behavior.

Are there any biodiesel fuel storage guidelines?

Use biodiesel fuel within six months of its manufacture date.  Biodiesel has lower oxidation stability compared to petrodiesel. Avoid storing equipment with biodiesel blends in the fuel system for more than three months.

What materials are incompatible with biodiesel?

Natural rubber, butyl rubber and some types of nitrile rubber (depending on chemical composition, construction and application) may be particularly susceptible to degradation.  Also, copper, bronze, brass, tin, lead and zinc can cause deposit formations.  The use of these materials and coatings must be avoided for fuel tanks and fuel lines. Fuel fittings and connectors are acceptable due to the small surface area in contact with the fuel.

Note:  Contact your vehicle manufacturer to determine if any of the OEM supplied components are at risk with biodiesel in order to prevent engine or vehicle damage.

Why didn't Cummins include engines prior to 2002?

The main reason not to include engines earlier than 2002 is due to materials compatibility concerns.  Some fuel systems in pre-2002 engines contain components that are not compatible with a B20 biodiesel blend.  EPA 2002 and later engines contain fuel system components that are compatible.

Why didn’t Cummins include high horsepower engines prior to January 1, 2008?

Some seals and gaskets had to be changed on the engines to allow compatibility with biodiesel.

How does using biodiesel affect the engine warranty?

Cummins engine warranty covers failures that are a result of defects in material or factory workmanship.  Engine damage, service issues, and/or performance issues determined by Cummins to be caused by the use of biodiesel fuel not meeting the specifications outlined in the Fuels Service Bulletin (3379001) are not considered to be defects in material or workmanship and are not covered under Cummins engine warranty.

This is no different from Cummins position with regular diesel fuel.  Cummins does not cover the damage caused by non-Cummins products that are of insufficient quality.  It is important to ensure when using diesel fuel or a B20 biodiesel blend with a Cummins engine that the fuel meets industry acceptable quality standards.

What are the implications of emission certification?

It should be emphasized that Cummins, in common with all other engine manufacturers, only certifies engines to meet the prescribed EPA (or other local regulatory agency) registered fuels.  It is the customer’s responsibility to use the correct fuel prescribed by these regulations and as recommended by the engine manufacturer.

The EPA has regulated the United States’ highway diesel fuel quality since 1993 to ensure it is compatible with engine emissions standards and air quality goals.  It is the responsibility of the customer to obtain the proper local, regional, or national exemptions required for the use of biodiesel in any emissions-regulated Cummins engine.

Will Cummins support the use of B20 biodiesel in engines not listed in this document?

Cummins fully supports the use of environmentally beneficial alternative fuels.  All of our automotive and industrial engines are compatible with B5 biodiesel to help encourage the greater use of renewable, domestically grown fuel.

Only engines listed in this document are approved for B20 use.  Cummins is continuing the evaluation of biodiesel concentrations higher than 5%.  All future products will be compatible with biodiesel B20. We are aware of the growing interest in B20 fuel blends and fully support this interest in renewable fuels.  As we reach conclusions and the completion of these evaluations, we will modify our position on engine compatibility accordingly.

Some OEMs using Cummins engines not listed in this bulletin may have specific releases regarding the use of biodiesel that apply only to their application.  All customers wanting to use biodiesel should also contact their OEM to ensure all supplied components are compatible, including fuel tanks and lines.

Is B20 approved for the RAM Turbo Diesel?

Cummins approves the use of up to B20 in the RAM trucks for municipal, government, and commercial fleets only.  This applies to selected model year vehicles.  Please consult Chrysler for specific requirements and approved vehicle models.