1. The filter element is made of low-price filter paper. Due to its large pore size, poor uniformity and low filtration efficiency, the impurities harmful to the engine cannot be effectively filtered, resulting in early engine wear.
2. Low quality adhesive is used, and the amount is very small. It is neither oil-resistant nor firmly bonded, resulting in short circuit at the bonding point of the filter element; Or the seams of the filter element are connected with staples, which cannot be sealed and short circuited, so that a large number of harmful impurities enter the engine and reduce the engine life.
3. Replace the oil-resistant rubber parts with ordinary rubber parts. During the use process or due to the failure of the internal sealing parts, the internal short circuit of the filter causes the early wear of the engine, the reduction of the service life, or the expansion and deformation of the external sealing parts, resulting in the extrusion of the outer sealing ring of the oil filter, and a large amount of oil leakage in a short time, causing the engine to burn, hold the shaft, and suffer serious damage.
4. Spot welding instead of seam welding is used for the welding of air filter shell parts, which can not guarantee the tightness and form a short circuit.

In addition, in the process of daily use, if the filter is blocked or too much dust is accumulated, the engine intake will be blocked, and a large amount of dust will enter the cylinder, which will accelerate the speed of carbon deposition in the cylinder, make the engine ignition not smooth, the power is insufficient, and cause the fuel consumption of the vehicle to increase.
Therefore, it is very expensive to use inferior filters. It is recommended that users be careful when replacing filters. It is better to choose original accessories to avoid unnecessary economic losses.