Diesel engines have four types of filters: air filter, oil filter, fuel filter, and cooling water filter, commonly referred to as "four filters". They are responsible for filtering impurities in the engine intake system, lubrication system, combustion system, and cooling water system.
The biggest harm to the working performance and lifespan of diesel engines is the impurities, particles, and pollution that enter the engine. They are the first 'killers' of engines. Filters are the only way to avoid foreign particles and pollution. With the advancement of engine technology, the requirements for filters are becoming higher and higher.
Due to the uneven quality of filter manufacturers. The filter was originally designed to filter harmful impurities from various substances entering the diesel engine. Enable the engine to operate normally under various operating conditions and achieve the specified service life.

However, inferior filters not only fail to achieve the aforementioned effects, but also bring various hazards to the engine. Common hazards include the following:
1. Using inexpensive filter paper to make filter cartridges, due to its large pore size, poor uniformity, and low filtration efficiency, it cannot effectively filter harmful impurities from the substances entering the engine, resulting in early engine wear.
2. Using low-quality adhesive that cannot be firmly adhered, resulting in a short circuit at the bonding point of the filter element; Allowing a large amount of harmful impurities to enter the engine will reduce the lifespan of diesel engines.
3. Replace oil resistant rubber parts with ordinary rubber parts. During use, due to the failure of internal sealing components, a short circuit is formed inside the filter, causing some oil or air containing impurities to directly enter the engine. Causing early engine wear.
4. The material of the center tube of the oil filter is thin instead of thick, and its strength is insufficient. During use, due to the center tube being compressed and the filter element being damaged, the oil circuit is blocked, resulting in insufficient engine lubrication.
5. Metal components such as the filter element end cover, center tube, and casing are not subjected to rust prevention treatment, resulting in metal rust and impurities, making the filter a source of pollution.