A lubricating oil composition having a HTHS viscosity at 150°C determined in accordance with ASTM D4683 in a range of 1.3 to 2.5 mPa.s (1.3 to 2.5 cP), comprising: (a) a major amount of an oil of lubricating viscosity having a kinematic viscosity at 100°C determined in accordance with ASTM D445 in a range of 1.5 to 6.0 mm 2 /s, wherein "major amount" means in excess of 50 weight % of a composition; and (b) an overbased metal salt of an alkyl-substituted phenolic-based detergent, wherein the alkyl group is derived from an isomerized normal alpha olefin having from 10 to 40 carbon atoms per molecule having an isomerization level (I) of the normal alpha olefin of from 0.1 to 0.4; wherein the isomerization level (I) of the olefin is determined by hydrogen-1 NMR obtained on a Bruker Ultrashield Plus 400 in chloroform-d1 at 400 MHz using TopSpin 3.2 spectral processing software, and the isomerization level (I) is: I = m/ m + n , where m is NMR integral for methyl groups with chemical shifts between 0.30 ± 0.03 to 1.01 ± 0.03 ppm, and n is NMR integral for methylene groups with chemical shifts between 1.01 ± 0.03 to 1.38 ± 0.10 ppm; and the alkyl-substituted phenolic-based detergent is a Ca alkylhydroxybenzoate compound; and the lubricating oil composition comprises 0.01 to 2.0 wt.% in terms of Ca content of the alkylhydroxybenzoate compound. (a) a major amount of an oil of lubricating viscosity having a kinematic viscosity at 100°C determined in accordance with ASTM D445 in a range of 1.5 to 6.0 mm 2 /s, wherein "major amount" means in excess of 50 weight % of a composition; and (b) an overbased metal salt of an alkyl-substituted phenolic-based detergent, wherein the alkyl group is derived from an isomerized normal alpha olefin having from 10 to 40 carbon atoms per molecule having an isomerization level (I) of the normal alpha olefin of from 0.1 to 0.4; wherein the isomerization level (I) of the olefin is determined by hydrogen-1 NMR obtained on a Bruker Ultrashield Plus 400 in chloroform-d1 at 400 MHz using TopSpin 3.2 spectral processing software, and the isomerization level (I) is: I = m/ m + n , where m is NMR integral for methyl groups with chemical shifts between 0.30 ± 0.03 to 1.01 ± 0.03 ppm, and n is NMR integral for methylene groups with chemical shifts between 1.01 ± 0.03 to 1.38 ± 0.10 ppm; and the alkyl-substituted phenolic-based detergent is a Ca alkylhydroxybenzoate compound; and the lubricating oil composition comprises 0.01 to 2.0 wt.% in terms of Ca content of the alkylhydroxybenzoate compound. the isomerization level (I) of the olefin is determined by hydrogen-1 NMR obtained on a Bruker Ultrashield Plus 400 in chloroform-d1 at 400 MHz using TopSpin 3.2 spectral processing software, and the isomerization level (I) is: I = m/ m + n , where m is NMR integral for methyl groups with chemical shifts between 0.30 ± 0.03 to 1.01 ± 0.03 ppm, and n is NMR integral for methylene groups with chemical shifts between 1.01 ± 0.03 to 1.38 ± 0.10 ppm; and the alkyl-substituted phenolic-based detergent is a Ca alkylhydroxybenzoate compound; and the lubricating oil composition comprises 0.01 to 2.0 wt.% in terms of Ca content of the alkylhydroxybenzoate compound. <EOS>