A positive crankcase ventilation oil mist separator system has a first separator unit, wherein the first separator unit includes at least one filter body arranged in a blow-by gas path such that blow by gas flows through the filter body; a second separator unit, wherein the second separator is an impactor separator arranged in a bypass path that bypasses the first separator unit; and a bypass valve, which opens the bypass path as soon as a differential pressure at the first separator unit exceeds a predefined value, wherein the second separator unit comprises an impact wall formed by a section of the filter body of the first separator unit, and a flow directing element which directs the blow-by gas flow against the impact wall when the blow-by gas path is open.