What Is a Oil Filter?
The oil filter is a cylindrical cartridge — either a spin-on canister or a replaceable paper element — mounted directly on the engine block. Engine oil circulates continuously under pressure through the oil filter, which traps metal particles, carbon deposits, combustion byproducts and other contaminants before they can circulate through the engine and cause damage to bearings, pistons and cylinder walls.
What Does the Oil Filter Do?
Engine oil lubricates every moving component inside your engine. As oil circulates it picks up fine metal particles from normal wear, carbon from combustion and other impurities. Without the oil filter continuously cleaning this oil, these abrasive particles would accumulate and dramatically accelerate engine wear. The oil filter also contains an anti-drain-back valve that keeps oil in the filter when the engine is off, ensuring immediate lubrication on startup.
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Get My Free Fault Scan →Symptoms of a Failing Oil Filter
A blocked or bypassed oil filter allows dirty oil to circulate through the engine. Symptoms include increased engine noise — particularly a ticking or tapping — reduced oil pressure, the oil pressure warning light, and visible darkening of the oil. In severe cases, restricted oil flow causes rapid bearing wear and can lead to catastrophic engine failure.
When Should the Oil Filter Be Replaced?
The oil filter should always be replaced at every engine oil change — typically every 10,000 to 12,000 miles on modern vehicles or every 12 months. Never replace oil without replacing the filter. A new oil filter costs between £5 and £25 depending on vehicle — a tiny cost compared to the damage a blocked filter can cause.
If you are experiencing symptoms related to your oil filter and are unsure whether it needs replacing, a free MotorLoom fault scan can help identify whether the component is likely at fault - giving you the most likely cause and estimated repair cost before you visit a garage.
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Related Parts
Other components that work alongside or are related to the oil filter: