The performance and projected longevity of a representative mineral-oil based CI-4 lubricant was evaluated using seven early production heavy-duty diesel engines tested under laboratory conditions. The 2003-2004 model year engines span the range from 5.9L to 15.2L and include engines with and without cooled EGR. All engines were evaluated using the same engine dynamometer cycle, fuel, and lubricant. The test cycle was based on the AVL 8-mode points, run as an 8-hour cycle, which stressed the oil with extended periods of operation ranging from idle to high load, but overall was considered a relatively low severity cycle.Oil analysis results display engine-to-engine differences in the rates of viscosity change, fuel dilution, soot accumulation, wear metal accumulation, total base number depletion, and oxidation. Overall, the 300-hour test results using the relatively mild cycle indicate that CI-4 lubricants are well suited for their intended application and that oil change intervals for EGR and non-EGR engines should be similar under “normal warm” conditions.