ABSTRACT
One trend in the use of engine oil in heavy duty diesel engines is to extend the time interval between oil drains. This technology requires the use of sophisticated additive packages including dispersants and detergents combined with the appropriate base stocks. In addition, adequate oil supply must be maintained over the extended use period. In the study described in this chapter, three engine oils, formulated with similar additive packages but different base oils, were evaluated in an extensive onhighway truck eet test. The engine lubricants were formulated with a conventional API Type I petroleum base oil, an API Type III low sulfur, high parafnic base oil and an API Type IV synthetic base oil. The change periods for the engine oils was extended to 75,000 miles for the Type I base oil formulation and 100,000 miles for the other two engine oils. All three engine oils performed satisfactory in the study.
