LUBRICATING OIL COMPOSITION FOR INTERNAL COMBUSTION ENGINE

To provide a lubricating oil composition for internal combustion engines which is capable of suppressing degradation of low-temperature fluidity when the composition is contaminated with water.SOLUTION: A lubricating oil composition for internal combustion engines includes: (A) a lubricating base oil including a mineral base oil and/or a synthetic base oil and having kinematic viscosity at 100°C of 3.8-4.6 mm2/s; (B) a metallic detergent including a salicylate detergent, which is 1000-2000 mass ppm in terms of a metal content or 10 mmol/kg or more in terms of the total amount of salicylate soap bases per kilogram of the composition; (C) 1.0 to 4.0 mass% of a comb-shaped poly(meth)acrylate having a weight average molecular weight of 350,000-1,000,000 and polydispersity of 4.0 or less; and (D) 100-1000 mass ppm, in terms of nitrogen, of a succinimide dispersant in which a non-modified succinimide and/or a boric acid-modified succinimide occupy 70 mass% or more of a total nitrogen content. The lubricating oil composition for internal combustion engines has HTHS viscosity at 150°C of 2.25 mPa s or more and less than 2.55 mPa s.SELECTED DRAWING: None 【課題】水混入時の低温流動性の悪化を低減することが可能な、内燃機関用潤滑油組成物を提供する。【解決手段】（Ａ）鉱油系基油及び／又は合成系基油からなり、１００℃動粘度が３．８～４．６ｍｍ２／ｓである潤滑油基油と、（Ｂ）サリシレート清浄剤を含む金属系清浄剤を、金属量として１０００～２０００質量ｐｐｍ且つ組成物１ｋｇあたりの全サリシレート石けん基の物質量として１０ｍｍｏｌ／ｋｇ以上と、（Ｃ）重量平均分子量が３５万～１００万かつ多分散度が４．０以下である櫛形ポリ（メタ）アクリレートを１．０～４．０質量％と、（Ｄ）無変性コハク酸イミド及び／又はホウ酸変性コハク酸イミドが全窒素分の７０質量％以上を占めるコハク酸イミド分散剤を、窒素分として１００～１０００質量ｐｐｍとを含み、１５０℃におけるＨＴＨＳ粘度が２．２５ｍＰａ・ｓ以上２．５５ｍＰａ・ｓ未満である、内燃機関用潤滑油組成物。【選択図】なし