Many car owners are now aware of the importance of oil, so they are very willing to pay more to upgrade oil for their cars. But do you know that when you focus all your attention on the oil, you ignore the oil filter. During engine operation, metal wear debris, dust, carbon deposits, colloidal deposits and water constantly mix with engine oil. The function of mechanical filter is to filter out these impurities, keep the engine oil clean and ensure its service life. In short, mechanical filter is a dirt collector.
 
Operating principle of oil filter and five general knowledge
1）. Oil filter composition: housing+filter element
1. Shell: the container used to hold the filter element to maintain the pressure operation, which is required to withstand high pressure without deformation and damage;
2. Fixed spring: it is used to fix the filter element and make it fixed and well sealed in the iron can during vibration and oil flow. Plate spring is also used;
3. Filter medium: used to filter sludge and impurities in engine oil, composed of filter paper and upper and lower end covers;
4. Central tube: used to support and fix the paper core;
5. Inner sealing gasket or check valve: used to prevent lubricating oil from flowing back to the oil pan when the engine stops working, to ensure that there is lubricating oil in the engine lubricating system for a long time, so that the engine can be lubricated immediately when it is just started;
6. Seal ring retainer: used to close the housing, fix the seal ring, and fix the oil filter on the engine;
7. Rubber sealing washer: the oil filter plays a sealing role when installed on the engine and is installed on the sealing ring seat;

2）. Function of oil filter: filter impurities
Generally, all parts in the engine work normally by lubricating the engine oil. However, the metal chips, dust, carbon deposits oxidized under high temperature and some water vapor generated during the operation of the parts will continue to mix with the engine oil. A long time will reduce the normal service life of the engine oil, which may affect the normal operation of the engine in serious cases.
Therefore, the role of the oil filter is reflected at this time. To put it simply, the function of the oil filter is to filter most impurities in the oil, keep the oil clean and extend its normal service life. In addition, the oil filter should also have strong filtering capacity, small flow resistance, long service life and other properties.

3）. Maintenance interval of oil filter: a vulnerable part
Under normal circumstances, dealers of all brands will classify oil filters as wearing parts. Take FAW Toyota as an example, the warranty period of oil filters is 6 months after the delivery date or within 10000 km. In terms of replacement, the engine oil and engine oil filter are basically replaced together. If it is used for a long time without replacement, the oil filter may lose its function and eventually affect the engine operation.

4）.  Distinguishing method of oil filter
1. Appearance: fine and rough
The fake oil filter has rough printing on the surface of the housing, and the font is usually vague. The factory logo on the surface of the real oil filter is very clear, and the surface paint texture is very good. Careful friends can easily see the difference through comparison.
2. Filter paper: filter capacity
The false oil filter has poor ability to filter impurities, which is mainly reflected in the filter paper. If the filter paper is too dense, it will affect the normal flow of oil; However, if the filter paper is too loose, a large number of unfiltered impurities will continue to flow with the engine oil, which will lead to dry friction or excessive wear of internal parts of the engine after a long time.
3. Bypass valve: auxiliary function
The bypass valve is a device for emergency oil delivery when the filter paper is blocked due to excessive impurities. However, the built-in bypass valve of most fake oil filters has no obvious effect, so when the filter paper fails, the oil can not be delivered in time, which will lead to dry friction of some parts in the engine.
4. Gasket: seal and oil leakage
Although the gasket looks a little inconspicuous, the sealing between parts depends on it. The gasket material in the fake oil filter is relatively poor, which may lead to its sealing failure under high temperature and high strength operation of the engine, and eventually lead to oil leakage.

5）. The secret of not wasting every drop of good engine oil
Engine oil (lubricating oil) plays an important role in engine protection, such as lubrication, cooling, cleaning, anti-corrosion and sealing; Only clean engine oil can complete the above work. Therefore, the overall performance of oil and oil filter is the decisive factor to determine the life of lubricating oil to protect the engine. In any case, it is unwise to choose high quality engine oil and use inferior engine oil filter at the same time.