Lubricating oil composition

Abstract

Lubricating oil compositions suitable for use in marine diesel engines comprise 60 to 85 parts by weight of lubricating oil, 15 to 30 parts by weight of a mixture of more than 50 wt .% of a Group IIa metal overbased detergent and up to 50 wt .% of a Group Ia metal overbased detergent and 0.2 to 5 parts by weight of an antioxidant, provided the weight ratio of the overbased detergent mixture to antioxidant lies between 7.5:1 and 50:1, all parts by weight referring to total active matter of the additive. When used in loop-scavenged crosshead marine diesel engines fouling of air ports with deposits is considerably reduced and there is a satisfactory anti-wear performance.

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