Genuine OEM Volkswagen Oil Separator, part number 03H103515A. This component is part of the engine's lubrication system, designed to separate oil from crankcase vapors and return oil to the crankcase. It is located in the position marked '29' in the diagram. The part weighs 0.609 kg. Genuine OEM oil separators are critical for maintaining engine health by preventing oil contamination and blow-by.