Patent ID: 7148186

Claim:
A method for enhancing wear prevention in a pressure accumulating diesel engine equipped with an exhaust gas recycle system and operating under lubricating conditions with large quantifies of soot in the oil, said amount of soot being in the 2.0 to 4.0 wt % range, by providing to the diesel engine a lubricating oil composition comprising a base oil selected from a mineral or synthetic oil incorporated with a combination of additives comprising a sulfurized oxymolybdenum dithiocarbamate at 0.03 to 0.50 wt % as Mo, a zinc dialkyldithio-phosphate at 0.04 to 0.50- wt % as P; and at least one metal salt of alkyl salicylate selected from the group consisting of a Ca salt of alkyl salicylate at 0.004 to 1.0 wt % as Ca; Mg salt of alkyl salicylate at 0.002 to 0.60 wt % as Mg, and Zn salt of alkyl salicylate at 0.006 to 1.60 wt % or Zn, all percentages being based on the whole composition, the degree of wear prevention enhancement being superior to that exhibited in said diesel engine lubricated by a lubricating oil which lacks the Ca, Mg or Zn salt of alkyl salicylate.