After on-site inspection, the maintenance personnel found that the O-ring of the 0R-3002 injectors was severely aging, hard and brittle, and even had cracks, leading to poor sealing and oil leakage. The reason for the aging of the O-ring was that the generator set had been working in a high-temperature environment for a long time, and the O-ring was affected by high temperature and oil erosion, resulting in accelerated aging. In addition, the O-ring had not been replaced during the previous maintenance.