Motor-vehicle air cleaner

A motor-vehicle air cleaner provided with a check valve mechanism (31) on the lower cap (23) of the air cleaner (2) for drainage and ventilation, and a protection (32) disposed on the outer edge; the check valve (31) being closed as the engine runs to prevent from taking in water vapor and dust; and check valve (31) being opened to dismiss water logging and excessively dense air and fuel admixture; the protection (32) is related to a protection cap to prevent the check valve mechanism (31) from direct contact with the ambient air for keeping off water and dust.