Patent ID: 6689726
Filing Date: 2004-02-10
Classification: C10M

Abstract:
A lubricating oil of reduced crystal formation potential, said formation potential attributable to the interaction of sulfur phosphorus containing anti-wear/extreme pressure agents and hindered phenolic autioxidants, comprising a major amount of a base oil of lubricating viscosity and having a saturates content of 99 wt % or more, and a minor amount of additives comprising a mixture of sulfur-phosphorus containing anti-wear/extreme pressure additive, a hindered phenol antioxidant, a high molecular weight di- or poly-carboxylic acid, anhydride or mixture thereof and an ester provided at least 0.0013 wt % high molecular weight carboxylic acid, anhydride or mixture thereof is present for each 1 ppm phosphorus attributable to the sulfur phosphorus containing anti-wear/extreme pressure agent, about 0.033 wt % or more ester is present for each 1 ppm phosphorus and the combination of high molecular weight acid, anhydride or mixture thereof and ester is employed in an ester to acid ratio of 25:1 by weight or higher.