●Filter paper: Oil filters have higher requirements for filter paper than air filters, mainly because the temperature of the oil varies from 0 to 300 degrees. Under drastic temperature changes, the concentration of the oil also changes accordingly, which will affect the filtration flow of the oil. The filter paper of a high-quality oil filter must be able to filter impurities under drastic temperature changes while ensuring sufficient flow.
●Rubber seal ring: The filter seal ring of high-quality oil is synthesized with special rubber to ensure 100% 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 generates pressure to supply oil to lubricate the engine. (Also called check valve)
●Overflow valve: Only available in high-quality oil filters. When the external temperature drops to a certain value or when the oil filter exceeds the normal service life, the overflow valve will open under special pressure to allow unfiltered oil to flow directly into the engine. Even so, impurities in the oil will enter the engine, but the damage caused by no oil in the engine is much less. Therefore, the overflow valve is the key to protecting the engine in an emergency. (Also called bypass valve).