Abstract: An automotive engine coolant composition includes: a non-silicone surfactant; an anti-foaming agent containing a mineral oil and silica; and a base, in which the base includes at least one alcohol selected from the group consisting of a monohydric alcohol, a dihydric alcohol, a trihydric alcohol, and a glycol monoalkyl ether and/or water, a kinematic viscosity is 8.5 mm2/s or more at 25° C. and 2.0 mm2/s or less at 100° C., and with respect to 100 parts by mass of the coolant composition, a content of the mineral oil is 0.01 to 0.4 parts by mass and a content of the silica is 0.003 to 0.1 parts by mass.

Abstract: An automotive engine coolant composition includes: a surfactant as a viscosity index improver; a rubber swelling inhibitor; and a base, in which the rubber swelling inhibitor is at least one selected from a compound expressed by a following formula (1) [in the formula, R1 is hydrogen, a methyl group, or an ethyl group] and a compound expressed by a following formula (2) [in the formula, R2 is hydrogen, a methyl group, or an ethyl group], the base includes at least one alcohol selected from the group consisting of a monohydric alcohol, a dihydric alcohol, a trihydric alcohol, and a glycol monoalkyl ether and/or water, a kinematic viscosity is 8.5 mm2/s or more at 25° C., and a content of the rubber swelling inhibitor is 0.03 parts by mass or more and 0.9 parts by mass or less with respect to 100 parts by mass of the coolant composition.

Abstract: An automotive engine coolant composition includes: a surfactant as a viscosity index improver; a rubber swelling inhibitor; and a base, in which the rubber swelling inhibitor is at least one selected from a compound expressed by a following formula (1) [in the formula, R1 is hydrogen, a methyl group, or an ethyl group] and a compound expressed by a following formula (2) [in the formula, R2 is hydrogen, a methyl group, or an ethyl group], the base includes at least one alcohol selected from the group consisting of a monohydric alcohol, a dihydric alcohol, a trihydric alcohol, and a glycol monoalkyl ether and/or water, a kinematic viscosity is 8.5 mm2/s or more at 25° C., and a content of the rubber swelling inhibitor is 0.03 parts by mass or more and 0.9 parts by mass or less with respect to 100 parts by mass of the coolant composition.

Abstract: An automotive engine coolant composition includes: a non-silicone surfactant; an anti-foaming agent containing a mineral oil and silica; and a base, in which the base includes at least one alcohol selected from the group consisting of a monohydric alcohol, a dihydric alcohol, a trihydric alcohol, and a glycol monoalkyl ether and/or water, a kinematic viscosity is 8.5 mm2/s or more at 25° C. and 2.0 mm2/s or less at 100° C., and with respect to 100 parts by mass of the coolant composition, a content of the mineral oil is 0.01 to 0.4 parts by mass and a content of the silica is 0.003 to 0.1 parts by mass.