CRANKCASE VENTILATION SYSTEM OIL SEPARATOR FLANGE. The crankcase ventilation system oil separator flange is a component of the engine crankcase ventilation system designed to mount and seal the oil separator to the crankcase ventilation assembly. This part ensures secure installation of the oil separator and proper routing of crankcase gases containing oil vapors from the internal engine space to the intake system or recirculation circuit. The primary function of the flange is to provide a sealed and durable connection between the oil separator and the engine housing or other components of the crankcase ventilation system. Through this connection, crankcase gases generated during engine operation are routed out of the crankcase to prevent excessive internal pressure. As these gases pass through the oil separator, oil particles are separated and returned to the engine lubrication system, while the cleaned gases are directed into the intake tract for further combustion. Structurally, the oil separator flange is typically a metal or high‑strength plastic component with mounting holes and internal passages for crankcase gas flow. Sealing elements are usually integrated into the design to maintain airtight connections and prevent leakage of gases or oil. Materials used in manufacturing are selected for resistance to engine oil, temperature fluctuations, vibration and aggressive crankcase gas environments. A properly functioning crankcase ventilation oil separator flange contributes to efficient engine ventilation, reduces oil vapor emissions and maintains stable pressure inside the engine crankcase. The catalog includes oil separator flanges for crankcase ventilation systems designed for gasoline and diesel engines used in passenger cars, commercial vehicles and specialized machinery.