Many car owners strictly replace the oil filter according to the cycle, but the oil still quickly turns black and dirty, which is not a problem with the quality of the oil filter, but rather the root cause lies in these aspects.

Firstly, the engine has serious carbon deposits. Old engines have insufficient combustion for a long time, resulting in a large amount of carbon deposits in the cylinders and intake ducts. During driving, the carbon deposits fall off and mix into the engine oil, causing the oil to quickly become dirty.
Secondly, the quality of the engine oil is poor. Using inferior, expired, and poorly adapted engine oil has poor antioxidant properties and is prone to oxidation and deterioration, resulting in oil sludge impurities.
Thirdly, the working conditions are too harsh, such as long-term short distance driving, frequent start stop, and congested idling. The oil cannot reach the optimal working temperature, and moisture and fuel mix into the oil, accelerating the deterioration of the oil and producing impurities.
Fourthly, there is residual oil sludge in the oil circuit, and the oil circuit and oil pan have never been cleaned. Old oil sludge continues to fall off and contaminate new engine oil.
Fifth, the internal wear of the engine is severe, and the aging and wear of components are exacerbated, resulting in the continuous production of a large amount of metal debris.

Solution:
Clean the engine carbon deposits and oil circuit, replace with high-quality compatible oil, improve driving conditions, shorten the filter replacement cycle, and solve the problem of easily dirty oil from the root.