Present-day fuels are stated to be the cause of crankcase-oil dilution, due to their high end-points, and the author presents tabular data to show how end-points have risen since 1910, together with data showing the effects of various percentages of fuel dilution with relation to the Saybolt viscosities and pour-points of high-grade oils. Three divisions are made of the dilution due to mechanical defects. Contamination, not dilution, necessitates oil drainage, and this statement is elaborated. The rise of heavier-bodied oils is decried.
Six specific divisions of how to avoid crankcase-oil dilution are made and emulsification is discussed, together with demulsibility and crankcase service. Five specifications are made with regard to how to avoid oil-sludging, and carbonization is given lengthy consideration. Proper oil-specification is treated, and instructions on how to avoid oil-pumping and carbon deposit are presented in eight divisions. Why education is needed on the three subjects of how to prevent crank-case-oil dilution, avoidance of oil-sludging and prevention of oil-pumping and carbon formation is explained in conclusion.