Automobile oil filter is one of the maintenance parts most frequently contacted by car owners.
Generally speaking, machine filters can be divided into two types: screw mounted (i.e. integrated) machine filters – machine filters with iron shell. Just unscrew the old machine filter and replace it with a new one, which is simple to operate; Modular (i.e. split or environment-friendly) machine filter – the machine filter of “naked” filter paper. When replacing, just open the oil filter shell and replace the filter element inside.

Although the structural forms of the two filters are different, they essentially filter out the impurities in the engine oil through the filter paper.
If you pay attention to observation, we can see that general high-end vehicles prefer split environmental protection filter. In addition to environmental protection, the environmental protection filter can also more intuitively see the quality of the filter paper. Of course, the main reason is that there are more parts for high-end cars, leaving an inch of land and an inch of money for the engine. Using the environmental protection filter can save more space. However, many car owners will find that the replaced environmental protection machine filter will have the waist retraction phenomenon as shown in the figure below. Will this phenomenon affect the filtering performance of the machine filter?

Then, why does the environmental protection machine filter retract at the waist? Will the waist retraction filter affect the filtering performance?
Cause:

Generally, there are two main reasons for this lumbar adduction:
1. If there are too many impurities in the engine oil, after 5000 km of use, due to the high filtering accuracy and large dust capacity of the machine filter, there are more impurities covered on the surface of the filter element after a period of use, resulting in the increase of oil pressure, which may cause the deformation of the engine oil filter element.

2. Due to the size difference between the inner diameter of the machine filter and the outer diameter of the support pipe, that is, there is a certain gap between the inner diameter of the machine filter and the support pipe. The waist position in the middle of the machine filter is the weakest position in the whole filter element. After using for a period of time, the pressure difference of the filter element continues to rise, and the oil pressure borne by the filter paper will become larger and larger, and then the waist position of the machine filter will sag inward.

Filter performance impact:

Note that if the replaced filter only shrinks inward at the middle of the waist, but the overall size, the welding condition between the upper and lower covers and the filter paper, and the flatness of the upper and lower covers of the filter are intact, it will not affect the filter performance of the whole filter and the product.