Genuine OEM Audi Engine Coolant Pipe, part number 4K0121081CA. This pipe is an essential component of the engine cooling system, responsible for circulating coolant to regulate engine temperature. It connects to the expansion tank, ensuring proper fluid flow throughout the system. Measuring approximately 0.39 meters in length, this pipe is designed for precise fitment and durability. Using a genuine OEM pipe ensures proper routing, material integrity, and resistance to thermal cycling and pressure, preventing leaks and maintaining cooling system efficiency.