Genuine OEM Audi Coolant Hose, part number 4E0121445AB. This vital component is responsible for carrying coolant between various parts of the engine cooling system, facilitating heat transfer and maintaining optimal engine operating temperature. It is positioned within the engine bay, connecting specific cooling system components as shown in the diagram. Weighing approximately 0.19 kg and measuring 0.35 meters in length, this hose is designed for durability. Using a genuine OEM coolant hose ensures correct routing geometry, material resistance to heat and pressure, and a leak-free connection, preventing costly engine damage.