Composition and characteristics of oil filter:

1. Filter paper:
The oil filter has higher requirements for filter paper than the air filter, mainly because the temperature of the oil varies from 0 to 300 degrees, and the filter paper of the high-quality oil filter should be able to filter impurities under severe temperature changes, while ensuring sufficient flow.
Note: low-quality filter paper is made of cotton pulp paper, the filtration effect is very poor, it is easier to decompose and dissolve into the oil, block the oil passage, accelerate the deterioration of the oil, and even no filter element will accelerate the engine damage.

2. Rubber seal ring:
The high quality oil filter seal ring is made of special rubber to guarantee 100% oil leakage.
Note: A good oil filter, under normal installation, will not leak oil. Poor quality, cheap oil spills are a problem.

3. Return suppression valve:
Only available in quality oil filters. When the engine is turned off, it can prevent the oil filter from drying out; When the engine is reignited, it immediately creates pressure and supplies oil to lubricate the engine. (also known as return valve)
Note: Maintain engine lubrication system pressure to reduce wear. Low-quality and inexpensive oil filters do not have check valves, accelerating engine starting wear.

4. Relief valve:
Only available in quality oil filters. When the external temperature drops to a certain value or when the oil filter exceeds its normal service life, the relief valve opens under special pressure, allowing unfiltered oil to flow directly into the engine and lubricate the friction parts - unfiltered impurities can increase engine wear. Therefore, the relief valve is the key to protect the engine in an emergency. (also known as bypass valve)
Note: Change the oil filter regularly (you need to change the oil filter every time you change the oil) to avoid accelerating engine wear due to the opening of the relief valve. There is no relief valve for low-quality filter, and in special cases, there is no lubricating oil supply, which will lead to the start of the cylinder, overhaul, and even scrap.

About oil leakage after changing the oil filter:
1. For the rotary filter (iron shell), the rotating force is too large, more than the standard 20-60 Newton (1 kg =9.8), the correct installation is installed with 2 kg of hand rotation, avoid installing with a wrench, the rotating force is greater than 2.5 kg, easy to cause the deformation of the sealing ring, a protrusion point along the circumference, high pressure air impact, resulting in gaps and leaks.
2. The flat dirt in contact with the old oil filter is not cleaned.
3. When removing the old oil filter, due to the previous rotation force is too large, the old sealing ring is stuck on the filter seat, and the new oil filter leaks oil after installation.
4. The lubrication system is seriously polluted, and heavy oil dirt blocks the main oil passage (or the sealant blocks the oil passage after overhaul), causing internal pressure and impacting the sealing ring leading to oil leakage.
5. For the environmental protection filter element (paper filter element), the vast majority of the sealing ring in the guide rod is not removed, and a new sealing ring is installed.
6. When the environmental protection filter element (paper filter element) is replaced, the new inner sealing ring is not replaced.
7. The environmental protection filter element (paper filter element) still has too much rotating force for the outer sealing ring (large), causing serious deformation or hidden injury, and it is affected by oil leakage under pressure during work.