Drill Master: Maintaining Emissions Compliant Engines

Owners and operators of late model diesel-powered trucks and off-road equipment are well aware of changing exhaust emission requirements. Some may wonder if the engines in their new off-road equipment have unique maintenance needs. The good news is proper care of non-road diesel engines still begins with the simple things such fluids and filters. This article will focus on some of the fluids that are important to a diesel engine.


From a service point of view, fuel is the fluid most likely taken for granted. The effects of using “bad” fuel can range from nuisance to disaster. Newer engines, designed to meet the latest emissions regulations, can be particularly sensitive to poor quality fuel. Users should always follow the fuel recommendations and requirements included in the operator’s manual for their equipment and engine. Those fuel requirements typically include meeting the specifications found in ASTM D975. Fuel purchased from reputable sources should easily meet these specifications.

Fuel Sulfur Content

 Sulfur content is an increasingly important characteristic of diesel fuel. Fuel sulfur level is measured in parts per million (ppm).  Environmental Protection Agency (EPA) rules require off-road fuel sulfur levels to be less than 500 ppm. This fuel is called low sulfur diesel (LSD). Starting in 2007, on-road truck engines have emission control devices that are sensitive to sulfur. Therefore, the EPA requires these engines to use fuel with a maximum sulfur content of 15 ppm. This fuel is called ultra low sulfur diesel (ULSD). Both LSD and ULSD can be sold as on-road fuel. However, for simplicity, many fuel stations carry only ULSD. It is easily identified by the required labels found on the pump. Off-road engines built since the mid-1990s can use either LSD or ULSD. However, due to ULSD’s lower lubricity, some older engines may experience difficulty when using that fuel. Operators of older engines should consult their equipment dealer or local engine distributor before using ULSD.

Finally, owners of small diesel-powered equipment may notice new labeling requirements. For all off-road engines smaller than 50 hp (and many smaller than 75 hp) and built in 2008 or later, the EPA requires a label at the fuel filler. That label must have this wording: “low sulfur fuel or ultra low sulfur fuel only.”


Nationwide, there is a rapidly growing interest in renewable fuels, such as biodiesel. Derived from vegetable oil or animal fat, biodiesel is typically blended with petroleum-based fuel. The term biodiesel may be used to describe either the pure renewable fuel or blended fuel. The portion of biodiesel in the blend is indicated by the letter “B” followed by a numerical value. For example, B20 indicates a blend of 20 percent biodiesel and 80 percent petroleum-based fuel. B5 and B20 are the common blend levels approved by equipment and engine manufacturers. Biodiesel users should follow their equipment and engine manufacturers’ fuel recommendations carefully. Exceeding the approved blend level will void the engine warranty in most cases.
Biodiesel’s quality can deteriorate more quickly than conventional fuel. The results of using poor quality biodiesel can range from filter plugging to piston failures. Operators should consult their equipment dealer or local engine distributor for more detailed information.

Lube Oil

The technologies used to meet stricter emissions rules can place new strains on diesel engine lube oil. To meet these challenges, the lube oil refiners develop performance criteria compatible with each new set of emissions rules. A simple way to keep up with these changing criteria is through The American Petroleum Institute’s (API) service category system. The latest API diesel service category, CJ-4, accommodates 2007 on-road engines using ULSD. As is usually the case, CJ-4 exceeds the criteria of earlier categories such as CI-4 and CH-4 and can be used in any four-stroke diesel engine. However, using CJ-4 with fuels other than ULSD can affect the service interval. Operators should always follow their equipment and engine manufacturers’ lube oil and service interval recommendations. If using API CJ-4 with non-road fuel (likely LSD), operators should check with their equipment and engine manufacturers for the recommended service interval. More information about lube oils can be found on API’s Web site at www.api.org/eolcs.


The service requirements for diesel engines meeting the latest emissions regulations are very similar to those for their predecessors. By simply following their equipment and engine manufacturers’ service recommendations, owners and operators can be confident their engines will give them many hours of faithful service.

David Campbell is project manager of engines and emissions compliance at The Charles Machine Works Inc. All Drillmaster Reports are reviewed by the Drillmaster Advisory Board: Frank Canon, Baroid Industrial Drilling Products; Richard Levings, The Charles Machine Works Inc.; Ron Lowe, Myers-Aplex Industries, a Pentair Pump Co.; Ed Savage, Vermeer Corp.; and Trevor Young, Tulsa Rig Iron.

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