Filter paper: The oil filter has higher requirements on the filter paper than the air filter, mainly because the temperature of the oil varies from 0 to 300 degrees. Under severe temperature changes, the concentration of the oil also changes accordingly. It will affect the filter flow of the oil. The filter paper of a high-quality oil filter should be able to filter impurities under severe temperature changes while ensuring sufficient flow.
●Rubber sealing ring: The filter sealing ring of high-quality oil is made of special rubber to ensure oil leakage.
●Backflow suppression valve: only available in high-quality oil filters. When the engine is turned off, it prevents the oil filter from drying out; when the engine is re-ignited, it immediately creates pressure to supply oil to lubricate the engine. (also known as a check valve)
●Relief valve: only available in high-quality oil filters. When the outside temperature drops to a certain value or when the oil filter exceeds its normal service life, the overflow valve opens under special pressure, allowing unfiltered oil to flow directly into the engine. Nevertheless, impurities in the oil will enter the engine together, but the damage is much less than the damage caused by no oil in the engine. Therefore, the relief valve is the key to protecting the engine in an emergency. (also known as bypass valve)