Every time the car is serviced, the little tin can on the car has to be unscrewed and replaced. This is our oil filter, which is replaced with the oil.

So here comes the question, how often does this oil filter usually need to be changed every kilometer? What is its longest lifespan? How long is its replacement cycle?

Before we understand this problem, let's take a look at this oil filter.

Our current oil filters are basically this spin-on oil filter. The outside is a round tin box, and the inside is folded filter paper. This filter paper is the core material of our machine filters. The current machine filter paper is heat-cured, so it has a certain hardness and strength. Unlike our ordinary paper, it can withstand oil pressure and is not easily deformed.

This oil filter is screwed into the middle part of the oil circuit. The bottom is the oil pan and the top is the engine. Its main function is to filter impurities and dirt in the oil, provide clean lubricating oil for the engine, reduce wear and prolong the service life of the engine.

Here's how it works. It has an oil inlet and an oil outlet. The oil in the oil sump flows into the filter from the oil inlet check valve. The dirty oil that flows in is on the edge of the filter, on the outside of the filter paper, and then filtered through the filter paper, and the clean oil flows out from the center of the filter and is sprayed to various parts of the engine.

This is the normal working process, but there will be some special cases. For example, our machine filter has been used for a long time, and the filter paper of the machine filter has too many impurities, which will block the pores of the filter paper and cause oil to flow out. If the amount is reduced, less oil will enter the engine, which will affect the lubrication and operation of the engine. what do I do?

In fact, at this time, in order to ensure the amount of oil flowing into the engine and maintain the oil pressure, there is a spring valve at the bottom of the oil filter, called a bypass valve, which will automatically open to allow unfiltered oil to flow out from the bottom valve. Go in, join with the oil in the center of the filter, and flow into the engine together, but at this time the mixed oil is oil with impurities.

How long do machine filters last?

In fact, the quality of our machine filter is not a problem, and the filter paper will not be deformed due to oil pressure and soaking in a short period of time.

However, the service life of the machine filter is mainly judged by its filtering ability, not its own quality. As we mentioned just now, if there are too many impurities and grease in the engine oil, it will adhere to the filter paper and block the filter holes, resulting in low oil pressure, so that the impurity oil directly enters the engine. This is equivalent to the fact that the oil has not been filtered. In fact, it is time to change the filter element at this time.

Therefore, the replacement of the machine filter depends on the cleanliness of the oil. Let's take an example. For example, we changed the oil and filter. If we ran 5,000 kilometers without changing the oil, we just changed the filter element, but the time to replace the new filter element next time will not reach 5,000. Kilometers, maybe 2000 kilometers, 3000 kilometers will be changed, because the old engine oil has more impurities than the new engine oil.

Therefore, in most cases, the oil filter has a service life of 5000 kilometers and is for new oil.