A method for utilizing a lubricating oil composition in which the content of a metal-based cleaning agent (X) having a base value of 100 mgKOH/g or less is 630 mass ppm or less in terms of metal atoms, and the content of sulfated ash is 1.5 mass % or less. The method includes measuring at least one physical property value among the capacitance and the dielectric constant of the lubricating oil composition while using the lubricating oil composition, and evaluating the progress of degradation of the lubricating oil composition.

A method for utilizing a lubricating oil composition in which the content of a metal-based cleaning agent (X) having a base value of 100 mgKOH/g or less is 630 mass ppm or less in terms of metal atoms, and the content of sulfated ash is 1.5 mass % or less. The method includes measuring at least one physical property value among the capacitance and the dielectric constant of the lubricating oil composition while using the lubricating oil composition, and evaluating the progress of degradation of the lubricating oil composition.

A lubricating oil composition is provided which comprises (a) greater than 50 wt. % of a base oil of lubricating viscosity; and (b) 0.1 to 40 wt. % of an overbased alkaline earth metal alkyl-substituted hydroxyaromatic carboxylate having a TBN, on an actives basis, of at least 600 mg KOH/g, as determined by ASTM D 2896; wherein the lubricating oil composition is a monograde lubricating oil composition meeting specifications for SAE J300 revised January 2015 requirements for a SAE 20, 30, 40, 50, or 60 monograde engine oil, and has a TBN of 5 to 200 mg KOH/g, as determined by ASTM D2896.

A lubricating oil composition is provided which comprises (a) greater than 50 wt. % of a base oil of lubricating viscosity; and (b) 0.1 to 40 wt. % of an overbased alkaline earth metal alkyl-substituted hydroxyaromatic carboxylate having a TBN, on an actives basis, of at least 600 mg KOH/g, as determined by ASTM D 2896; wherein the lubricating oil composition is a monograde lubricating oil composition meeting specifications for SAE J300 revised January 2015 requirements for a SAE 20, 30, 40, 50, or 60 monograde engine oil, and has a TBN of 5 to 200 mg KOH/g, as determined by ASTM D2896.

Alkyl salicylic acids, overbased detergents derived from alkyl salicylic acids, lubricating compositions including the alkyl salicylic acids and/or overbased detergents, and processes of making and using the same, are described.

The present disclosure describes lubricant compositions effective to minimize average engine sludge through selection of lubricant additives that control the total nitrogen as well as the origin of the nitrogen in the lubricant composition. In aspects, the lubricant compositions herein include at least a base oil of lubricating viscosity, a dispersant system, and at least one antioxidant.

A lubricating oil composition may include a base oil (A), succinimide (B) which has not been modified with boron, succinimide (C) modified with boron, a metallic detergent (D), and an antioxidant (E), wherein the ratio of the content of boron atoms derived from ingredient (C) to the content of nitrogen atoms derived from ingredients (B) and (C), B/N, is 0.30 or less by mass, the lubricating oil composition satisfying requirement (I) and/or requirement (II). Requirement (I): Ingredient (D) includes a metallic detergent (D1) having a base value less than 100 mgKOH/g. Requirement (II): Ingredient (E) includes an amine-based antioxidant (E1), the content of ingredient (E1) being 1.00 mass % or less.

A lubricating oil composition containing a base oil (A), a comb-shaped polymer (B), and an olefin-based copolymer (C), wherein a content of the component (B) is more than 0.80 mass % based on the total amount of the lubricating oil composition, a weight average molecular weight of the component (C) is 500,000 or more, and the lubricating oil composition has a viscosity index of 200 or more and a kinematic viscosity at 100° C. of 9.3 to 11.0 mm.sup.2/s.

A lubricating oil composition containing a base oil (A), a comb-shaped polymer (B), and an olefin-based copolymer (C), wherein a content of the component (B) is more than 0.80 mass % based on the total amount of the lubricating oil composition, a weight average molecular weight of the component (C) is 500,000 or more, and the lubricating oil composition has a viscosity index of 200 or more and a kinematic viscosity at 100° C. of 9.3 to 11.0 mm.sup.2/s.

An ammonium-based ionic liquid compound including a tri-n-octylmethylammonium cation and a carboxylate anion. A lubricant composition including it, and its use as a detergent and/or anti-corrosion additive in a lubricant, in particular a marine lubricant.