Ensure the excavator is on a stable surface and turned off.

Engage the parking brake and remove the key from the ignition.

Wear safety gloves and goggles to protect yourself.

Locate the diesel oil tank cover on the Sany 55 excavator. Depending on the model, you may need to remove any surrounding panels or covers to access it.

If you are replacing an old or damaged cover, carefully unscrew or unclip it from the tank. Keep any screws or fasteners, as you will need them for the new cover.

Check the sealing surface on the diesel oil tank for any debris, dirt, or damage. Clean the area thoroughly with a rag to ensure a proper seal with the new cover.

Position the new diesel oil tank cover over the opening of the tank. Ensure that it aligns properly with any mounting points or grooves.

If the cover has a gasket, ensure it is in place and properly seated.

If the cover uses screws or bolts, tighten them securely using the appropriate tools. Be careful not to overtighten, as this could damage the cover or the tank.

Ensure that the cover is seated correctly and that there are no gaps between the cover and the tank. A proper fit is essential to prevent leaks.

Before starting the excavator, double-check that the cover is securely fastened and that there are no visible leaks or issues.

Start the excavator and allow it to run for a few minutes. Monitor the area around the diesel oil tank cover for any signs of leaks.