Topics:
Oil Filter:
The oil filter’s task is to remove contaminants from the oil. Dirt particles larger than 5µm (0.005mm) are captured in the paper filter element. By filtering the oil, the engine will have a longer lifespan, as dirt particles like metal and carbon can damage the engine’s components. Therefore, the oil filter must be replaced periodically. This nearly always coincides with changing the engine oil, which typically occurs between 9,000 and 18,000 miles or every 1 or 2 years.
There are various types of oil filters. The images below show two different oil filters.
Spin-On Filter: This is a widely used oil filter. It consists of a metal housing containing a paper filter element. During a service, the entire filter is replaced, including the metal housing.
If too many dirt particles are present in the paper filter element, it may become clogged. Causes can include severe engine contamination from driving too long with old engine oil or an old oil filter. To prevent blocking the entire oil supply to the engine, the bypass valve will open against spring tension. At that moment, oil does not flow through the paper filter element but exits directly from the filter housing. Consequently, the oil is not filtered, and dirt particles will circulate within the engine.
Replaceable Filter Element: The replaceable filter element is located under a screw cap on the engine. This cap can be metal or plastic and often requires a special oil filter wrench to remove. During maintenance, only this paper filter element is replaced, not the entire metal filter housing with bypass valve, etc.
In the image below, this type of oil filter is disassembled. The paper filter element can be snapped out of the plastic cap, and the new one can be snapped in. Never forget to replace the rubber ring on this cap and lightly lubricate it with oil before reinstalling the filter. If the rubber ring is not lubricated, it may tear during installation.
This type of oil filter is often mounted on the top side of the engine. Therefore, it’s important to disconnect it before draining the engine oil. A significant amount of oil still flows into the sump when the filter is disconnected. The oil filter housing contains a valve that ensures the oil filter does not drain when the engine is turned off. This prevents a few seconds of no oil pressure each time the engine is started. For this reason, the filter remains filled. Always disconnect the oil filter first, preferably remove it, and only then drain the oil.
Related pages: