Genuine OEM Jaguar Crankcase Breather Valve, part number AJ87773. This valve plays a crucial role in the engine's ventilation system, regulating pressure and allowing blow-by gases to escape the crankcase. This prevents the buildup of harmful pressure, which can lead to oil leaks and seal damage, while also contributing to emission control. Weighing approximately 0.03 kg, this plastic valve is designed for precise function. Using a genuine OEM valve ensures correct calibration and material resistance to engine contaminants, vital for maintaining engine health and compliance with emission standards.