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What is Oil Filter in Cars: Functions, Types, Parts and Signs of Failure

The engine of a car is a complex system where various components work in harmony to ensure optimal performance. Among these, the oil filter plays a pivotal role in maintaining the engine's health and longevity.

Understanding the intricacies of oil filters, their types, functions, and signs of failure can significantly contribute to the overall health of your car's engine.

What is an Oil Filter?

An oil filter is designed to remove impurities and contaminants from engine oil, ensuring that only clean oil circulates through the engine. An oil filter is a small yet mighty device that plays a pivotal role in maintaining a car's engine health.

Clean oil is essential for optimal engine performance and longevity, making oil filters a crucial component in any car.

What are the Functions of Oil Filters?

Oil filters are very important to keep your car's engine healthy, their functions include:

  • Particle Collection: Oil filters efficiently collect particles such as dust and metal shavings that can otherwise cause damage to engine components.
  • Maintenance of Engine Cleanliness: The main goal of oil filters is to keep the oil clean so that the engine can always work well.
  • Soot Filtration: Oil filters play a crucial role in filtering out soot, a byproduct of combustion, which can be harmful if allowed to accumulate in the engine.
  • Thinning Holes: Oil filters have tiny holes that stop thickened oil from entering the engine, keeping things running smoothly.
  • Protecting Rods: Oil filters ensure moving parts like connecting rods stay safe by stopping tiny bits that can cause damage.
  • Protecting Camshaft and Valvetrain: Camshaft and valvetrain parts need clean oil to work right. Oil filters help with this, making these parts last longer.
  • Reduce Wear: A well-functioning oil filter minimises friction and wear between moving engine parts, enhancing the overall lifespan of the engine.
  • Damage Prevention: Oil filters act as a barrier against potential damage; they keep sensitive engine parts safe, ensuring the engine works well for a long time.

What are the Major Parts of Oil Filters?

An oil filter consists of several parts working together; the important parts of an oil filter are:

  • Tapping Plate: Tapping plate has small holes around the edge that let oil flow in. The centre hole is where oil goes out, facing the engine.
  • Antidrainback Valve: Prevents oil from going back when the engine is off. It's needed because the filter is often in the middle or bottom of the engine.
  • Filter Medium: The filter has a unique material with tiny fibres. It's strong, and some have synthetic fibres for better performance. High-quality filters use synthetic fibres.
  • Pleats: The folded filter material makes more space to catch dirt. The number of folds depends on how thick the material is.
  • Center Steel Tube: It gives structure to the filter and lets clean oil go back to the engine. The size and position of holes make sure oil flows well without blockage.
  • Relief Valve: When the engine is cold, the oil is too thick to filter. The relief valve opens to let unfiltered oil in until there's enough pressure. It prevents the engine from starving.
  • End Disc: An end disc made of fibre or metal stops unfiltered oil from entering the centre tube. It's attached to both ends of the filter material.
  • Retainer: Like a metal leaf spring, a retainer keeps the filter material and end disc tight against the tapping plate.

What is the Working Principle of Oil Filter?

Oil filters work simply. Oil comes in through tiny holes on the edge, cleans up inside, and returns to the engine through a giant hole.

Most filters today have a rubber valve, like a membrane, near the holes. It opens when oil flows in under pressure and closes when the engine is off. This keeps oil in the filter and prevents engine damage when starting.

Modern engines have a backup filter called a bypass filter. It helps in extreme conditions like very cold weather, where thick oil can cause issues. If the primary filter is clogged, oil can still go through the bypass filter, ensuring the engine stays protected.

What are the Types of Oil Filters?

Oil filters come in various types, each with its unique functionality; six common types of oil filters are:

  • Full Flow Oil Filter: This type filters all the engine oil before reaching critical engine components, providing comprehensive protection.
  • Cartridge Oil Filter: Cartridge oil filters use a replaceable filter element housed in a metal casing, allowing easier maintenance.
  • Spin-On Oil Filter: It is a convenient and commonly used type, featuring a self-contained unit that can easily be replaced during regular maintenance.
  • Secondary or By-Pass Oil Filter: These filters work with the primary filter, providing additional filtration for enhanced engine protection.
  • Spinner Oil Filter: Spinner oil filters use a spinning action to separate contaminants from the oil, ensuring effective filtration.
  • Magnetic Oil Filter: This type utilises magnets to attract and capture metallic particles, preventing them from circulating in the engine.

What are the Symptoms of Bad and Failing Oil Filters?

Regularly checking your car for signs of a failing oil filter is important; here are the signs of a bad oil filter:

  • Bad Engine Performance: A decrease in engine performance, including reduced power and efficiency, may indicate a clogged or failing oil filter.
  • Sputtering: Irregular engine sputtering or misfiring can result from inadequate oil flow caused by a clogged or malfunctioning filter.
  • Metallic Sounds: Unusual metallic sounds, such as knocking or tapping, may signal internal engine damage due to insufficient lubrication.
  • Dropping Pressure: A sudden drop in oil pressure can be a sign of a failing oil filter, leading to inadequate lubrication of engine components.
  • Dirty Exhaust: Contaminated oil can result in dark and dirty exhaust emissions, indicating a potential issue with the oil filter.

In the intricate web of automotive maintenance, the humble oil filter stands as a guardian, shielding your engine from potential harm. Understanding its functions, types, and signs of a failing filter empowers car owners to make informed decisions, ensuring their vehicles continue to run smoothly.

FAQs about Oil Filters in Cars

How often should an oil filter be changed?

An oil filter should be changed every 8,000 to 10,000 kilometres for optimal engine performance and longevity. Regular replacements ensure the filter effectively removes contaminants and maintains proper lubrication.

Why are oil filters so expensive?

The cost of oil filters may be higher due to the quality of the filtration medium, other internal elements, and the materials used for the gasket.

Is it OK to change the oil but not the filter?

No, when changing engine oil, always replace both the oil filter and oil together. Avoid just changing the oil and ignoring an old filter, even if it seems okay.