1. Fuel filter replacement
The replacement interval specified due to changes in fuel filter performance depends on the type of fuel filter used. The fuel filter outside the fuel tank is usually maintained every 48-96km. The fuel filter inside the fuel tank is usually exempt from maintenance. When replacing the fuel filter, it should be operated on a cold engine to avoid igniting the fuel in the hot exhaust manifold.

2. Oil circuit and oil pipe maintenance
If the car is equipped with an external fuel filter, during the maintenance and upkeep of the filter, it is necessary to check the external oil pipes and circuits connected to the fuel filter, observe whether there is any damage on its surface, and replace it in a timely manner. Many new fuel filters are equipped with two new rubber oil pipes, which are connected to both ends of the fuel filter and then connected to the oil circuit. After using the new rubber tubing, the old tubing should be discarded. Release the clamping device and disconnect the oil circuit, while blocking the oil circuit to prevent fuel overflow.

Most fuel filters installed in the fuel circuit have an in and out arrow to indicate the direction of fuel flow when passing through the filter, which points towards the engine. The clamping device used on the oil circuit is a special type, and its design performance fully meets the requirements of sealing oil pipes and fuel filter joints.

3. Maintenance of fuel filter joints
Many imported cars use circular joints on their fuel filters. For this type of annular joint combination component, the sealing gasket is not allowed to be reused. When tightening the joint, the sealing gasket must be replaced to prevent fuel leakage. If not used carefully, it will cause thread misalignment or excessive tightening of the joint.

If the car is equipped with a non repairable fuel system and a fuel filter built into the fuel tank, considering the cost, even if the regular preventive maintenance interval of the car is long, it is impossible to replace all the fuel pumps and fuel output devices of the fuel filter. However, if there is abnormal engine performance or if the fuel pressure in the fuel system is at a critical value, it is necessary to check and replace the fuel filter placed in the fuel tank.

4. Fuel filter and oil circuit inspection
After reassembling everything, you can reinstall the fuel pump fuse and then turn the engine for a few minutes with the ignition system not working until the fuel pressure is established. Check the fuel filter and circuit to ensure there are no fuel leaks. If everything is normal, start the engine and run it for a few minutes, then check again for any leaks.