Genuine OEM Audi engine vent tube, part number 420103218E. This tube is a critical component of the crankcase ventilation system, responsible for routing blow-by gases back into the intake for combustion. It is designed to withstand high engine temperatures and oil exposure while maintaining a secure, airtight connection. Genuine OEM parts are essential for ventilation systems to ensure the correct material durability, heat resistance, and precise routing geometry required to prevent vacuum leaks and maintain optimal engine performance.