The principle of Freiga engine oil rotor filter is to filter out impurities in engine oil, make pure engine oil enter the engine, prevent impurities from wearing engine parts, ensure the normal use of automobile engines and prolong the service life of parts. The installation methods of oil filter are: 1. Drain or suck up old oil; 2. Loosen the fixing screw and remove the old oil filter; 3. Apply a layer of oil to the sealing ring of the new oil filter; 4. Install a new oil filter and tighten the fixing screws.