Plug screws with code EN47R13 are critical sealing components in the MAN L21/31 engine, used to close threaded openings in oil, fuel, or cooling systems. Designed to resist pressure, temperature fluctuations, and vibration, these screws ensure leak-free operation and protect internal systems from contamination. Their reliable sealing performance and robust construction make them a key element in maintaining engine cleanliness, safety, and consistent performance during prolonged operation.