ENGINE COOLANT COMPOSITION FOR AUTOMOBILE, CONCENTRATED ENGINE COOLANT COMPOSITION FOR AUTOMOBILE AND OPERATION METHOD OF INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide an engine coolant composition for an automobile, which has a specific kinematic viscosity by an appropriate thickening effect of a surfactant as a viscosity characteristic improving agent and which suppresses foaming property of the surfactant, and a concentrated engine coolant composition for an automobile for obtaining the above composition.SOLUTION: The engine coolant composition for an automobile comprises the following components: (A) a silicone-based oil compound; (B) a polyether-modified silicone; (C) non-silicone-based surfactant; and (D) a base agent. The silicone-based oil compound (A) comprises the following components: (A1) at least one compound selected from organopolysiloxane represented by general formula (1) below; and (A2) a filler. The polyether-modified silicone (B) is at least one compound selected from polyoxyalkylene-modified organopolysiloxane represented by general formula (2) below. The base agent comprises at least one alcohol selected from the group consisting of monohydric alcohol, dihydric alcohol, trihydric alcohol and glycol monoalkyl-ether, and/or water. The coolant composition has a kinematic viscosity of 8.5 mm/sec or more at 25°C and 2.0 mm/sec or less at 100°C.SELECTED DRAWING: None