Automotive three filters refer to air filters, oil filters and gasoline filters. Three filters play a role in filtering air, oil and gasoline on the car engine, improving the working efficiency of the engine. 

1. The oil filter is generally required to be replaced every 5000 kilometers. The more common one is that the filter paper is installed in the cylindrical aluminum shell, and it only needs to be screwed in the installation position when replacing it. Because the engine oil circulates in the engine oil passage to the cylinder wall heat dissipation and lubrication, and the control of the valve clearance, the worn metal chips and hot coking will be filtered through the oil filter. If the oil filter element is not changed when changing the oil, the dirty oil in the filter element still exists;
2. The most common air filter is a dry filter paper type, which is the kind of yellow-green or white filter element. As long as the air filter element is taken out of the filter element box and blown with high-pressure air, it is necessary to replace it when it is found to be dirty and cannot be blown clean with high-pressure air during maintenance of about 10,000 to 20,000 kilometers. The oil-bath-type filter element almost never needs to be replaced, as long as every two kilometers or so, the oily and dirt on it are cleaned with a lotion during maintenance, and it can be used again after it is fully dried and refilled with new oil;
3. Gasoline filter is abbreviated as steam filter. Gasoline filters are divided into carburetor type and electronic injection type. For gasoline engines using carburetor, the gasoline filter is located on the inlet side of the fuel transfer pump, and the working pressure is relatively small. Generally, a nylon shell is used. The gasoline filter of an EFI engine is located on the outlet side of the fuel transfer pump, and the working pressure is relatively high. A metal shell is usually used.