The O-ring, code 06.56936-2985.0, is a compact yet indispensable sealing element used across multiple systems of the MAN L21/31 engine to ensure leak-free operation. Designed with a precise elastic profile, it deforms under compression to create a tight seal between mating surfaces, effectively preventing the escape of fluids and the ingress of contaminants. Manufactured from high-performance elastomer materials resistant to heat, oil, and chemical exposure, the O-ring maintains flexibility and sealing integrity even under fluctuating pressures and temperatures. Its reliable performance supports system efficiency, protects critical components, and reduces maintenance demands in both marine and stationary diesel engine applications.