Genuine OEM Audi Coolant Pipe, part number 4E0121399H. This rigid pipe is an integral part of the engine cooling system, responsible for transporting coolant between various components to regulate engine temperature. The diagram indicates its specific routing within the cooling circuit. Weighing approximately 0.369 kg with dimensions of 0.49m x 0.225m x 0.075m, it is typically constructed from durable metal or high-strength plastic. Using a genuine OEM coolant pipe ensures exact dimensions, correct material properties, and secure connections, which are vital for preventing leaks and maintaining the efficiency of the cooling system.