B5.9G, B5.9LPG, B Gas Plus, B LPG Plus – 018-003   Lubricating Oil Recommendations and Specifications

Table of Contents

General Information

General Information




Do not use L10G engine oil in the B5.9G, B Gas Plus, B Gas International, B5.9LPG, B LPG Plus, C8.3G, C Gas Plus, L Gas Plus, and ISL G engines. If L10G engine lubricating oil is used, failure of the tappets and camshaft will occur.

Do not use diesel engine oil in a natural gas engine. If diesel engine oil is used, valve torching, piston scuffing, and reduction of spark plug life will occur.

A sulfated ash limit of 0.6 percent has been placed on all engine lubricating oil recommended for use in Cummins® natural gas engines. Higher ash oils can cause valve and/or piston damage and lead to excessive oil consumption and degradation of the catalyst.

Cummins® natural gas engines require a special oil that is available from major oil suppliers. Careful attention must be paid to engine oil specifications, because natural gas engine oil has different properties than diesel engine oil.

The oil specification for the B5.9G, B Gas Plus, B Gas International, B5.9LPG, B LPG Plus, C8.3G, C Gas Plus, L Gas Plus, and ISL G engines is not the same as the L10G engine lubricating oil specification.

B5.9G, B Gas Plus, B Gas International, B5.9LPG, B LPG Plus, C8.3G, C Gas Plus, L Gas Plus, and ISL G engines must use oil that conforms to Cummins Engineering Standard (CES) 20074. This standard will be identified on the supplier’s oil packaging. If in doubt as to whether the oil meets the Cummins Inc. specification, contact the supplier to obtain a copy of the Cummins registration letter that certifies the oil meets specifications.

For easy identification, the packaging of the oil will show CES20074 upon it.

For further assistance, contact a Cummins® Authorized Repair Location, which can supply information regarding oil brands that comply with Cummins Inc. specifications.

Correct engine lubricating oil and filter change intervals must be maintained for each specific Cummins® engine model. A sharp increase in component wear and damage can occur if lubricating oil and filter maintenance intervals are not followed as outlined in the maintenance schedule in Section 2.

Quality engine lubricating oils combined with appropriate oil and filter change intervals are critical factors in maintaining engine performance and durability.

Special “break-in” engine lubricating oils are not recommended for new or rebuilt Cummins® natural gas engines. During “break-in”, use the same lubricating oil that will be used in normal engine operation.


As the engine oil becomes contaminated, essential oil additives are depleted. Lubricating oils protect the engine as long as these additives are functioning properly.

Progressive contamination of the oil between oil and filter change intervals is normal. The amount of contamination will vary, depending on the operation of the engine, distance on the oil, fuel consumed, and new oil added.

NOTE: Oil for natural gas engines does not darken and look dirty as diesel oil does. Use the maintenance schedule in Section 2 to determine the oil change interval requirement, not the oil’s appearance.

Additional information regarding lubricating oil availability throughout the world is available in the E.M.A. Lubricating Oils Data Book for Heavy-Duty Automotive and Industrial Engines. The data book can be ordered from the following:

Engine Manufacturers Association
2 North LaSalle Street
Suite 2200
Chicago, IL, U.S.A. 60602
Phone 1-312-827-8700

For further details and discussion of engine lubricating oils for Cummins® engines, refer to Cummins® Engine Oil Recommendations, Bulletin 3810340.

Last Modified:  16-May-2007