AUTODOC BLOG

EXPERT IN AUTO PARTS

21 May 2025 (updated)

Car Engine Oil Filter: Types, Functions, Symptoms, and Replacement Prices

Table of content

Car oil filter functions
How does a car oil filter work?
Types of oil filters
Car oil filter design
Operation features of the oil filter
What oil filter do I need?
Bad oil filter symptoms
Best oil filter brands
How often to change an oil Filter
Can you change the oil filter without changing the motor oil?
The cost of an oil filter change
1. Everything you need to know about the oil filter
2. Top products related to this topic

Engine oil is essential for lubricating, cooling, and protecting your car’s engine, but over time, it collects dirt, metal particles, and debris. A quality oil filter is crucial to trapping these contaminants and ensuring clean oil circulates, preventing premature wear and damage. In this blog, we'll guide you through choosing the right oil filter for your specific vehicle, as well as outline the costs of a replacement.

Car oil filter functions

So, what exactly does an oil filter do? Its primary purpose is to ensure that the oil is purified before it flows through the engine to prevent buildups of contaminants and sludge, allowing the lubricant to properly do its job. Without it, the motor’s moving parts would wear out more quickly and there is a higher risk of oil starvation due to blockages and therefore total engine failure.

The oil filter is designed to clean the engine oil. Together, they perform the following functions:

Draw heat away from the engine component surfaces, which get hot due to friction and the combustion process
Remove dust, soot, and metal particles
Create a protective oil film that prevents friction between metal contact surfaces
Reduce engine noise while operating

How does a car oil filter work?

A car engine oil filter traps contaminants from the oil before it enters and reenters the engine. Oil flows to the oil filter via the oil pump. As the lubricant enters the filter, it passes through small holes into the filtration chamber. Inside the component, there is a specially designed filtration element, usually made of synthetic fibres, cellulose, or a combination of both. It is pleated to increase the surface area and its efficiency.

Types of oil filters

There are four main types of engine oil filters:

Spin-on: self-contained units with a metal canister and a replaceable filter inside.

Cartridge: replaceable filter element placed inside a reusable housing, often more eco-friendly than spin-on filters.
Magnetic: use magnets to attract and capture metal particles in the oil, providing long-lasting engine protection.
Centrifugal: use centrifugal force to separate contaminants from the oil, spinning out impurities into a separate chamber for collection.

In addition, filters can be categorised as primary (full-flow) and secondary (bypass) filters according to how much oil they clean at one time.

Full-flow: it filters 100% of the oil flow before it enters the engine. An important component of this filter type is that it often includes a bypass valve that controls pressure in the engine lubrication system. If the pressure level exceeds the permissible values (for example, when the filter element is clogged), the valve will open the access of dirty oil to the engine units. The valve operation prevents damage to lubrication system seals and gaskets, and protects the engine from faults caused by low levels of lubricant on the surface of its components.
Bypass: this is a secondary filter that provides finer filtration. The parts are typically used in conjunction with full-flow filters. The engine lubrication system in this case consists of two circuits. Once the oil has been through the initial filtration stage in one circuit, a small amount of it passes through the bypass filter to ensure that even the tiny particles are removed. Eventually, the filter cleans all the oil circulating in the system.

P 7210 BOSCH F 026 407 210 Oil filter M 20 x 1,5, Spin-on Filter

Reviews - 82

BOSCH Oil filter M 20 x 1,5, Spin-on Filter

Article number: F 026 407 210

£ 5,77

price incl. 20% VAT, excl. delivery costs

P 7204 BOSCH F 026 407 204 Oil filter Filter Insert

Reviews - 40

BOSCH Oil filter Filter Insert

Article number: F 026 407 204

£ 13,50

price incl. 20% VAT, excl. delivery costs

P 3079 BOSCH 0 451 103 079 Oil filter M 18 x 1,5, Spin-on Filter

Reviews - 59

BOSCH Oil filter M 18 x 1,5, Spin-on Filter

Article number: 0 451 103 079

£ 4,47

price incl. 20% VAT, excl. delivery costs

P 7188 BOSCH F 026 407 188 Oil filter M 22 x 1,5, Spin-on Filter

Reviews - 33

BOSCH Oil filter M 22 x 1,5, Spin-on Filter

Article number: F 026 407 188

£ 8,68

price incl. 20% VAT, excl. delivery costs

P 7299 BOSCH F 026 407 299 Oil filter Filter Insert

Reviews - 43

BOSCH Oil filter Filter Insert

Article number: F 026 407 299

£ 8,36

price incl. 20% VAT, excl. delivery costs

More time is needed to remove impurities in this way. Using a bypass filter helps to keep the pressure in the system at a certain level even if the filter is clogged or the bypass valve has failed. Filters can be designed as a one-piece component or with an assembled housing. The assembled parts are cheaper to maintain as you only have to replace the filter element inside.

Car oil filter design

The design of an oil filter is important because it directly affects its filtration efficiency, durability, and ease of maintenance. Not all vehicles require the same design, and some parts are more straightforward to replace than others. For example, the most common type, the spin-on filter, can be easily installed by simply screwing it on with an oil filter wrench.

Lube oil filter design

The part has a metal casing that houses two valves and a filter element. The anti-drainback valve prevents the oil backflow when the engine is not in operation. The bypass valve provides the oil flow into the engine when the component fails, the element is clogged, the oil viscosity has increased, or the anti drainback valve is jammed.

Operation features of the oil filter

This part is used in quite harsh conditions. It is constantly exposed to temperature changes caused by engine combustion, as well as chemical reactions. This is why the material the filter element is made of must be resistant to thermal and chemical influences and provide consistent filtration for oils of varying viscosities. It is advised to replace most oil filters at least once every 7 000–10 000 km. Don't neglect these recommendations: using parts that have exceeded their service life, as well as buying poor-quality consumables, poses a risk of engine failure.

What oil filter do I need?

First of all, to choose the right oil filter for your car, check your vehicle's owner's manual for specific recommendations. You must ensure that the product is compatible with the specific oil type (conventional or synthetic). Moreover, if you drive in harsh conditions, opt for products with advanced features like enhanced filtration. Finally, verify that the size matches that of the original component to ensure a proper fit and performance.

Other things to consider:

Pay attention to the purification efficiency of the filter paper as it must comply with technical requirements of your car. In passenger car engines, the filter must provide oil filtration for 5 micron particles. Well purified oil extends the overall service life of the engine and its components. Please note that the higher the level of purification is, the lower the flow capacity tends to be.
Inspect the filter housing. The valves and seals must be fully tight.
Carefully examine information about the manufacturer. As a rule, the companies that produce high-quality filters always include their company details on the packaging, including the country of origin and the customer support phone number.
When purchasing the item online, you should only use trusted online shops or retailers. They usually offer expert help and a warranty or quality guarantee.

4044130000 HENGST FILTER E523H D373 Oil filter Filter Insert

Reviews - 1

HENGST FILTER Oil filter Filter Insert

Article number: E523H D373

compared to RRP £ 40,41

£ 34,54

price incl. 20% VAT, excl. delivery costs

P 7123 BOSCH F 026 407 123 Oil filter Filter Insert

Reviews - 110

BOSCH Oil filter Filter Insert

Article number: F 026 407 123

£ 10,65

price incl. 20% VAT, excl. delivery costs

P 7225 BOSCH F 026 407 225 Oil filter 3/4" 16 UNF, Spin-on Filter

Reviews - 4

BOSCH Oil filter 3/4" 16 UNF, Spin-on Filter

Article number: F 026 407 225

£ 6,48

price incl. 20% VAT, excl. delivery costs

70367063 MAHLE ORIGINAL OC 534 Oil filter 3/4" 16UNF 2B, 3/4"-16UNF-2B, Spin-on Filter

Reviews - 90

MAHLE ORIGINAL Oil filter 3/4" 16UNF 2B, 3/4"-16UNF-2B, Spin-on Filter

Article number: OC 534

compared to RRP £ 10,22

£ 5,52

price incl. 20% VAT, excl. delivery costs

72483059 MAHLE ORIGINAL OC 1566 Oil filter M20x1,5, Spin-on Filter

Reviews - 44

MAHLE ORIGINAL Oil filter M20x1,5, Spin-on Filter

Article number: OC 1566

compared to RRP £ 10,35

£ 6,36

price incl. 20% VAT, excl. delivery costs

Bad oil filter symptoms

Common symptoms of a failed filter include:

Decreased engine performance due to restricted oil flow caused by a clogged filter
Unusual engine sounds such as ticking or grinding noises
Oil leaks around the filter area
Low oil pressure warning light on the dashboard
Dirty or dark oil despite regular oil changes
Engine overheating caused by insufficient lubrication
Poor fuel economy
Metallic particles in the oil
Excessive exhaust smoke

Best oil filter brands

Castrol

Known for its high-performance oils and filters, Castrol is a prominent manufacturing company that focuses on advanced filtration technology to ensure optimal engine protection and longevity.

Mobil

A subsidiary of ExxonMobil, Mobil produces a range of premium-quality oil filters designed for both conventional and synthetic oils, enhancing engine performance and efficiency under various driving conditions.

Mannol

Mannol is a well-respected brand in the automotive sector, offering quality oil filters and lubricants that provide excellent filtration and protection, catering to a diverse range of vehicles and applications.

Pemco

A leading manufacturer specialising in automotive products, Pemco offers reliable oil filters that prioritise engine health and performance, ensuring effective contamination control and extended service life.

Shell

An oil industry giant, Shell produces high-quality oil filters designed to work seamlessly with its motor oils and match the exact requirements of each vehicle application.

How often to change an oil Filter

It is generally recommended that you change the oil filter whenever you change the oil itself. In most cases, the standard change interval is between 3,000 and 7,500 miles. Some filters have to be replaced as often as every 6 months. However, this will also depend on the age of the vehicle and the driving conditions.

Can you change the oil filter without changing the motor oil?

While you can theoretically change the filter without adding new oil, it is often advisable not to do so. This is due to the fact that changing the lubricant prevents old, contaminated oil from recirculating and causing blockages and wear. It may also be more economical.

The cost of an oil filter change

As prices have increased, the average price of an oil and filter change in the UK currently stands at around £110 with typical prices ranging between £60 and £200. The costs will vary depending on the specific vehicle model, the parts required by the manufacturer, and where you get the replacement done. If you change the filter yourself, you may be able to reduce the price by eliminating labour costs.

A useful video on this topic: