The method of draining the diesel filter assembly:
1. Drain water under the diesel oil-water separator, unscrew the small cap under the filter, and close the oil inlet and outlet at both ends;
2. The function of the diesel filter is to filter out harmful impurities and moisture in the fuel system, protect the normal operation of the engine, reduce wear, avoid blockage, and improve engine life;
3. The filter elements of diesel filters are mostly made of filter paper, and some are made of felt or polymer materials. The filter elements of gasoline filters are mostly made of filter paper, and some also use nylon cloth and polymer materials;
4. The structure of the diesel filter is roughly the same as that of the oil filter, and there are replaceable and spin-on types.

The in-line fuel filter, which is outside the outer tank, is connected to the return line; the built-in fuel filter is located in the tank:
1. Gasoline filter element is also called gasoline grid, gasoline filter, we collectively call it a gas filter. First of all, let's understand the function of the steam filter: the function is to filter out the iron oxide, dust contained in the gasoline, and solid impurities such as harmful particles and moisture in the fuel system. It can protect the fuel injector, cylinder liner, piston ring and other components, prevent the fuel system from clogging, reduce the wear of automobile engine parts, and ensure the stable operation of the engine;
2. The main function of gasoline filter is to filter out impurities in gasoline. If the gasoline filter is too dirty or clogged, the main manifestations are: when the throttle is added, the power is slow, or it cannot be started, and the car is difficult to start;
3. Gasoline is refined from crude oil through a complex process, and then transported to various refueling stations through special channels, and finally delivered to the owner's fuel tank. In this process, impurities in gasoline will inevitably enter the fuel tank, and in addition, with the extension of use time, the impurities will also increase. In this way, the filter used to filter the fuel will be dirty and full of dregs. If this goes on, the filtering effect will be greatly reduced.