The seal ring, code 136973, is a critical sealing component within the MAN L21/31 engine, designed to prevent leakage of fluids and maintain controlled pressure conditions across various mechanical and hydraulic systems. Installed at key sealing interfaces, it forms a reliable barrier against oil, fuel, coolant, or air leakage while accommodating operational movement and thermal expansion. Manufactured from durable, wear-resistant, and chemically resistant materials, the seal ring retains its sealing performance even under high pressure, vibration, and elevated temperatures. By ensuring system tightness and protecting critical engine sections from contamination or pressure loss, the seal ring contributes directly to engine efficiency, operational safety, and extended service life.