After on-site inspection, the maintenance personnel found that the oil leakage was concentrated at the connection between the injector body and the cylinder head, and a small amount of oil stains were also found on the surface of the injector. By disassembling the 0R-3190 injectors, it was found that the sealing gasket between the injector and the cylinder head was severely aged and deformed, and the sealing surface of the injector body had slight wear, resulting in poor sealing and fuel leakage. In addition, during the daily maintenance process, the maintenance personnel did not torque the injector fixing bolts according to the standard requirements, leading to uneven force on the sealing gasket and accelerating its aging.