Genuine OEM Audi Engine Coolant Pipe, part number 4L0121397B. This pipe carries coolant to regulate engine temperature, forming a vital part of the cooling circuit. It is positioned within the engine cooling system, connecting various components. Weighing 0.128 kg and measuring 0.48 m in length, this pipe is designed for precise fit. Genuine OEM coolant pipes ensure correct routing geometry, material integrity, and resistance to thermal cycling and pressure, preventing leaks and maintaining cooling efficiency.