<div class="htmlview paragraph">Because the analyses of many samples of new and of diluted crankcase oil had not been completed by the Bureau of Standards when the results of the winter tests were reported at the 1923 Semi-Annual Meeting, the report on these dilution data was delayed. This information has since become available and forms the basis of this paper.</div> <div class="htmlview paragraph">After reviewing the results of the winter tests as already reported, stating the names of the cooperating companies and tabulating the cars and the mileage distribution in the test runs, the author discusses the results of the analyses of fresh crankcase oils and the dilution results before making a comparison between those obtained under summer and under winter conditions.</div> <div class="htmlview paragraph">Dilution versus mileage, the subjects of dilution, viscosity and specific gravity and the distillation of composite oil samples are presented next, followed by comments upon crankcase-oil consumption. Numerous tables and charts are included, and a summary of the results is made. In the <span class="xref">appendix</span>, a report is made of a set of parallel runs with both a commercial gasoline and a special winter fuel that was conducted by one of the cooperating companies in addition to the regular tests described in this paper and in the previous report.</div>