Abstract: A two-stage oil separator for crankcase ventilation includes a housing having a lower end and an upper end. The lower end communicates with the crankcase and the upper end communicates with an exhaust system. The housing defines an internal flow channel extending generally upwards from the lower end toward the upper end. A first-stage filter element is disposed proximate the lower end and includes a first filter media of relatively coarser porosity. A second-stage filter element is disposed proximate the upper end and vertically upward of the first-stage filter element. The second-stage filter element includes a second filter media of relatively finer porosity than the first filter media.