Why does the diesel filter do not need a bypass valve, but the machine filter does. What’s the difference?

01 Why does the diesel filter do not need a bypass valve, but the machine filter does. What’s the difference?

The bypass valve is a safety valve to prevent the oil filter from clogging, causing poor lubrication of the engine, and then damaging the parts. Because the engine will not stop when the filter is blocked, and the engine will stop when the diesel filter is blocked, and the parts will not be damaged. Therefore, the diesel filter does not need a bypass valve.

02 The role of the bypass valve and check valve in the oil filter

Many oil filters are equipped with bypass valves and check valves, but few people know their role. Let us briefly introduce the functions and functions of its components.

Bypass valve

When the installation position of the filter is facing downwards or in a horizontal position, if the engine stops working, the oil will flow back to the oil pan, resulting in no oil in the oil filter. But when the engine is started next time, in order to ensure the safety of the engine, the oil must be refilled in the entire lubricating system, which prolongs the time for the lubricating oil to reach the lubrication of the engine body and increases the wear of the engine body.

Check valve

The function of the check valve is to prevent the oil in the filter from draining, and to ensure that the filter is full of oil at any time. When the engine is restarted, the oil can reach the engine body for lubrication almost instantly.

When the filter element in the filter is blocked due to excessive impurities, the bypass valve will open, and the lubricating oil will directly enter the engine for lubrication without passing through the filter element. The bypass valve is designed for emergency lubrication, so as not to cause more serious dry wear of the engine due to lack of lubricating oil.

In other words, the bypass valve of the oil filter element prevents the oil from leaking when the local oil pressure is too high and the rubber ring is damaged after the oil filter is blocked. If the diesel filter element is dirty, the car will be weak. If it’s blocked, it won’t start, so it can be found.