Car engine oil filter: importance, types and maintenance

The oil filter in a car's engine is one of the most important components that helps ensure the smooth running and long life of your engine. This small but important part plays a vital role in maintaining the quality of your engine oil and protecting the internal components of your engine from damage. In this article, we'll explore the function of an oil filter, the different types, how it works, and why regular maintenance is essential.

What is an engine oil filter?

An engine oil filter is a device that cleans engine oil by removing dirt, sand, metal particles, and other contaminants. The oil filter is usually located near the oil pan or in the engine block, and its purpose is to protect the internal components of the engine by ensuring that the oil circulating in the engine is clean and free of harmful substances that can damage the engine's working parts. Clean oil is important because it lubricates the engine's moving parts and prevents overheating.

Oil filter function

When a car engine is running, friction and heat are generated from the movement, which cause dirt, sludge and small metal particles to build up in the oil. Over time, these contaminants build up in the oil, making it less effective at lubricating the engine. An oil filter helps remove these particles before they reach sensitive parts of the engine, protecting things like pistons, camshafts and bearings from wear.

The main functions of the oil filter are as follows:

1. Filtration of contaminants : The oil filter removes dirt, dust and metal particles from the oil.
2. Keeping the oil clean : The oil filter ensures that the oil remains clean and effective.
3. Preventing engine wear : Clean oil helps reduce friction and wear in the engine, extending engine life.
4. Optimizing engine performance : Clean oil ensures that the engine's moving parts are properly lubricated, which results in smoother operation and better performance.

Oil filter types

Today's cars use a variety of oil filters, with different designs and filtration capabilities. The most common types are:

1. Spin-on oil filters :

Threaded-type oil filters are the most common and consist of a metal housing containing the filtering material. They are easy to replace and often have a rubber seal on them to ensure a tight seal around the oil.

Spin-on oil filters are one of the most common types of oil filters found in vehicles. They have a disposable housing that contains the filter and other components. These filters are easy to install and replace during regular oil changes. Spin-on filters typically provide reliable filtration and are available in a variety of filtration levels to suit different engine requirements and driving conditions.

• how they work:
  Threaded-in filters are self-contained units that screw onto the engine. They contain the filter media and metal housing in one piece.
• advantages:
  • quick and easy to install.
  • wide selection for different vehicles.
• disadvantages:
  • more waste as the entire filter is replaced.
  • not as environmentally friendly as cartridge filters.

 

2. Full flow oil filters :

Most modern vehicles use full-flow oil filters. These filters allow all of the engine oil to pass through their filter, ensuring that every drop of oil is clean before it reaches the engine.

The full-flow filter is also one of the most common. It filters all the oil pumped through the engine. This type of filter is designed to prevent friction and severe engine clogging. It also allows the oil to move more freely in the engine.

• how they work:
  Full-flow filters filter all the oil used by the engine before it reaches the engine components. These are usually mechanical filters.
• advantages:
  • effectively protects the engine as all the oil passes through the filter.
  • Low flow resistance ensures correct oil pressure.
• disadvantages:
  • higher filter material consumption.
  • may not remove very small particles.

3. Bypass oil filters :

1. how they work:
   Bypass filters only filter a portion of the oil, allowing for a higher degree of cleaning because the oil moves through the filter more slowly. The rest of the oil goes directly into the engine.
2. 
3. advantages:
   • can remove very small particles.
   • extends oil and engine life.
4. disadvantages:
   • does not filter all the oil at once.
   • more suitable for heavy-duty engines, not for everyday vehicles.
5.  

6. These filters work in conjunction with full-flow filters to further purify the oil. Some of the oil is routed through a bypass filter to remove fine particles that the main filter cannot capture.

   4. Magnetic oil filters

These filters use magnets to attract and trap metal particles in the oil. They are typically designed for high-performance or heavy-duty engines where metal particles are more likely to be present.

• how they work:
  use magnets to capture metallic contaminants, such as iron filings, from the oil.
• advantages:
  • can remove metal particles that other filters may not catch.
  • durable and easy to maintain.
• disadvantages:
  • does not trap non-metallic particles.
  • requires additional filter elements to remove other contaminants.

 

5. Cartridge filters - filter element (cartridge oil filters)

These filters only contain a filter element that can be replaced, while the filtration housing remains. They are more environmentally friendly as they produce less waste.

 

• how they work:
  The filter element is housed in a separate housing that is attached to the engine. To replace the filter, only the filter element needs to be replaced.
• advantages:
  • more environmentally friendly because the metal casing is not thrown away.
  • easy to maintain.
• disadvantages:
  • may be more time-consuming than replacing thread-type filters.
  • requires a special tool to remove the filter element.

 

How does an oil filter work?

An oil filter works by passing engine oil through its filter media, which can be made of paper, synthetic material, or mesh. The oil flows into the filter and is then forced through the filter media, where contaminants are trapped. Clean oil exits the filter and returns to the engine to lubricate moving parts.

Oil filters are typically designed to withstand a certain oil flow rate to ensure proper filtration while not impeding the normal flow of the engine. If the oil filter becomes clogged with dirt, oil flow can be restricted, leading to increased wear on engine parts and potentially engine failure.

Oil filter construction

A classic oil filter consists of the following parts:
1. Case. Protects the filter element and withstands high pressure to prevent the filter from leaking.
2. Relief valve. Ensures continued oil flow to the engine in an emergency situation where the element is clogged or when starting a cold engine. This protects the engine.
3. Filter media. A highly efficient material that filters out foreign matter and dirt from the oil to protect the engine from wear and damage.
4. Support tube. Holds the filter element in place to ensure the best filtration.
6. Anti-drain valve. Ensures that oil does not flow back after the car engine stops. The oil pressure in the lubrication system reaches its specified level faster, which protects the engine after starting.
7. Bottom assembly plate. Resists high pressure and prevents filter deformation.
8. gasket. Ensures that there is no oil leakage between the bottom plate and the engine.

The importance of oil filter maintenance

Regular oil changes are important not only for changing the oil, but also for changing the oil filter. Most expert recommendations say that the oil filter should be changed with every oil change to ensure that the new oil remains clean and can still effectively protect the engine.

The importance of oil filter maintenance:

1. Preventing oil filter clogging : When the oil filter becomes clogged, oil can begin to bypass the filter and recirculate along with contaminants, which can cause wear on engine parts.
2. Optimizing engine performance : Clean oil is essential for proper engine lubrication, which helps maintain engine performance and efficiency.
3. Reducing repair costs : Neglecting to change the oil filter can lead to engine failures that are costly to repair.

How to change a car oil filter?

Changing an oil filter is usually a simple task, but it requires the right tools and knowledge of car maintenance. Follow these steps to change your oil filter:

1. Gather the necessary tools : You will need a new oil filter, the correct amount of engine oil, an oil filter wrench, a drain pan, and gloves.
2. Drain the old oil : Place a drain pan under the oil pan, remove the drain nut, and allow the oil to drain completely.
3. Remove the old oil filter : Use an oil filter wrench to remove the old oil filter. Be careful as the oil filter may still contain old oil.
4. install a new oil filter : take a new oil filter, lubricate its rubber seal with a small amount of fresh oil and screw it firmly into place by hand (do not overtighten).
5. Add new oil : After changing the oil filter, fill the engine with the correct amount and type of oil.
6. Check for leaks : Start the engine and let it run for a few minutes, then check the oil filter and drain nut for leaks.

Common Oil Filter Problems by Car Brand and Engine

Below are recurring observations from practice, not accusations toward manufacturers. These are typical situations where the wrong filter or improper maintenance can quickly cause problems.

Volkswagen / Škoda / SEAT / Audi

Typical problems

• Incorrect installation of cartridge filters

• Incorrect gasket placement

• Deformation of low-quality filters

Symptoms

• Oil pressure warning light during cold start

• Metallic noise during the first seconds

• Oil leaks around the filter housing

Causes

• Incorrect filter height or diameter

• Weak anti-drainback valve

• Failure of the filter’s internal structure

In these engines, the oil filter is often located at the top of the engine, which means an incorrect filter quickly causes oil pressure issues.

BMW

Typical problems

• Collapse of the filter element

• Oil pressure fluctuations

• Rapid filter clogging

Symptoms

• Timing chain or camshaft noise

• Oil pressure warnings

• Uneven engine operation when cold

Causes

• Filter material that is too soft

• Long service intervals

• High operating temperature

BMW engines are particularly sensitive to filter quality, not just the oil itself.

Mercedes-Benz

Typical problems

• Gasket leaks

• Incorrect filter height

• Uneven sealing of the filter

Symptoms

• Oil stains on the engine

• Smell of oil

• Slow increase in oil pressure

Causes

• Non-original filters

• Incorrect tightening torque

• Double gasket installation

Mercedes-Benz engines often have oil filter housings with very precise tolerances.

Ford

Typical problems

• Anti-drainback valve failure

• Dry start during cold start

• Rapid filter clogging

Symptoms

• Knocking noise when starting

• Delay in oil pressure build-up

• Uneven idle

Causes

• Low-quality filter

• Poor valve quality

• Short trips

Peugeot / Citroën

Typical problems

• Filter clogging

• Rapid oil contamination

• Gasket leaks

Symptoms

• Oil pressure warning light

• Engine noise

• Oil darkening quickly

Causes

• Long service intervals

• High temperatures in turbo engines

• Poor-quality filter

Toyota / Lexus

Typical problems

• Filter element failure

• Incorrect filter seating

• Oil draining back

Symptoms

• Engine ticking when cold

• Oil pressure delay

• Unstable operation

Causes

• Incorrect filter type

• Excessively long replacement interval

• Low-quality filter

Most Common Mistakes When Choosing and Replacing Oil Filters

• Wrong filter (similar but not exact)

• Not replacing the filter together with the oil

• Not lubricating the gasket

• Incorrect tightening torque

• Leaving the old gasket in place

These mistakes are among the main causes of oil leaks and pressure problems.

Summary

The engine oil filter is an essential part of a car engine, protecting the engine from dirt and contaminants, ensuring clean oil and effective lubrication. Regular oil changes, along with oil filter changes, are an easy and effective way to ensure a long engine life. Changing the oil filter helps prevent engine wear and ensures that your car runs in optimal condition, saving you time and money in the future.