Genuine OEM Audi Cooling Breather Line, part number 4G0121081AE. This essential component is part of the engine cooling system, designed to allow trapped air to escape, preventing airlocks and ensuring proper coolant flow. It is positioned on the front left side of the engine bay. This line is typically made from heat-resistant plastic or rubber, ensuring durability and a leak-free connection. Weighing only 0.016 kg, its specific routing and connection points are critical for effective cooling. Using a genuine OEM breather line guarantees precise fitment, correct material properties, and reliable performance, which are crucial for maintaining optimal engine operating temperatures.