• Image
    To visualize how oils compare, engineers use “spider graphs.” The spider web-like graphs have multiple linear axes along which results are plotted. Each axis represents a specific attribute. As attributes are added, axes are inserted accordingly. The further from the center zero point on each axis, the better the performance. Each new specification requires new tests, as shown here. Source: Chevron
Contingency Plans

The following are a couple of useful end-user tips:

For non-road equipment users: Government agencies operate on- and off-highway equipment as well as stationary equipment.

Stationary engines are allowed fuel with up to 5000 ppm sulfur (S5000). Mandated sulfur levels for non-road equipment will drop to 500 ppm this month, but will not be required to meet S15 standards until June 2010.

Because of low SAPS, most oil suppliers recommend against using CJ-4 in non-road diesel engines, but CJ-4 will work if you shorten drain intervals.

For 2007 engines: If faced with an emergency situation when you must add oil to a 2007 vehicle but only have an older oil, you can top off—provided you drain the oil at the earliest possible time, then refill with the new oil. CI-4 Plus will not harm the engine, but its additives will speed the contamination of the DOC and will affect DPF life-to-cleanout, depending on how much oil is added and how long it stays in.

For some readers, CI-4 Plus will do for everything. Others should change to CJ-4, balancing higher costs with expected benefits of longer engine life. Still others will find it worthwhile to store and use both grades, but should take care not to get them mixed up.

SIDEBAR: In the past, new diesel oil formulations were “backward compatible,” meaning they could be used instead of previous formulations and performance would increase in almost every respect. As a result, the preceding grade of oil quickly disappeared.

But CJ-4, the oil developed for engines with 2007 emissions controls, uses different technologies. And because CJ-4 is so different, most suppliers will continue to provide the older CI-4 Plus for the foreseeable future.

To see a visual comparison of the oils, click here

— Paul Abelson (truckwriter@anet.com) is a former director of the Technology and Maintenance Council of the American Truck Association, a board member of Truck Writers of North America, and active in the Society of Automotive Engineers.