The O-ring K 27275 is a small but crucial sealing element specified for housings K 27259 and K 27263 on the Sulzer ZV40/48 fuel system. Installed between mating faces, this O-ring prevents high-pressure fuel leaks and protects surrounding components from contamination. Made from a fuel-resistant, heat-stable elastomer, it must tolerate pressure pulsations and vibration while retaining elasticity. Because O-rings are wear items, keeping spares and checking for hardening, cuts or compression set during routine inspections is a simple, high-value step to avoid fuel loss and maintain safe, reliable operation.