The vehicle air filter mileage is about 20000 km, and the oil filter mileage is about 5000 km. Filter refers to the accessory used to filter impurities or gases through filter paper. Generally, it refers to the automobile filter, which is a part of the engine. The following is the classification of automotive filters:
1. Air filter, the air filter is installed in front of the carburetor or intake pipe to filter dust and sand in the air and ensure sufficient and clean air in the cylinder; Replace after the mileage is about 20000 km;
2. The engine oil filter is located in the engine lubrication system, which is used to filter harmful impurities in the engine oil from the oil pan and supply clean engine oil to the crankshaft, connecting rod, camshaft, supercharger, piston ring and other motion pairs to lubricate, cool and clean, thus extending the life of these parts; Replace after 5000 km;
3. Air conditioner filter, commonly known as pollen filter, is used to filter the air entering the compartment from outside to improve the cleanliness of the air; The mileage of replacement cycle is about 10000 km;
4. The fuel filter is used to filter harmful particles and water in the engine fuel gas system, so as to protect the oil pump nozzle, cylinder liner, piston ring, etc., reduce wear and avoid blockage. Filter the iron oxide contained in the fuel. The replacement cycle shall be subject to the vehicle maintenance manual.

The gasoline filter is called steam filter for short. Gasoline filter can be divided into carburetor type and electronic injection type:
1. For gasoline engines using carburetors, the gasoline filter is located at the inlet side of the fuel transfer pump with low working pressure and generally adopts nylon shell. For electric injection engines, the gasoline filter is located at the outlet side of the fuel transfer pump with high working pressure and usually adopts metal shell;
2. Filter paper is mostly used as the filter element of the gasoline filter, and nylon cloth and polymer material are also used as the gasoline filters. The main function is to filter impurities in the gasoline. If the gasoline filter is too dirty or blocked;
3. Linear filter paper gasoline filter: the gasoline filter is inside this type of gasoline filter, and the folded filter paper is connected with both ends of the plastic or metal filter. After the dirty oil enters, it is filtered by layers of filter paper from the outer wall of the filter to the center, and the clean fuel flows out.