What filters are changed when changing engine oil?

Scheduled vehicle maintenance is not just a formality, but a critical process for extending the life of the power unit. Many car owners mistakenly believe that it is enough to simply drain the waste and fill it with fresh synthetics, ignoring the condition of the filter elements. However, it is what filters are changed when changing the oil?, determines how long the engine will operate without complaints and costly repairs.

During the combustion of the fuel-air mixture and the friction of metal parts, wear products are formed, which, without proper cleaning, quickly turn engine oil into an abrasive mess. If you ignore replacing consumables, you risk experiencing oil starvation, scuffing of the crankshaft liners, and even jamming of the piston group. Let's take a closer look at what elements require attention and why saving on them is detrimental.

The main element without which the maintenance procedure is impossible is oil filter. It is he who takes the lead in cleaning the lubricating fluid from metal shavings, carbon deposits and oxidation products. Inside this small cylinder there is corrugated paper impregnated with special resins, which traps particles up to 10-20 microns in size. If this element is not replaced, the bypass valve may become clogged and dirty oil will go directly into the lubrication system without being cleaned.

Oil filter: the heart of the lubrication system

The oil filter is the main consumable, which must be replaced every time the lubricant is renewed. Its design can be simple, in the form of a cartridge, or more complex, with an integrated housing. In modern engines such as Toyota Camry or BMW 3 Series, compact replaceable elements are often used, whereas on classic models like Lada Granta Full-flow glass filters are still popular. The quality of filtration directly affects the resource rubbing couples engine.

There is a bypass valve inside the housing, which opens during a cold start, when the oil viscosity is high, or when the filter element is heavily contaminated. This prevents oil starvation but allows unrefined lubricant to pass through. The design also includes an anti-drainage valve that prevents oil from draining from the filter after stopping the engine, which makes starting easier. Ignoring replacement This unit leads to rapid wear of hydraulic compensators and phase regulators.

⚠️ Attention: Never use oil filters of questionable quality or without original packaging. Cheap analogues may not withstand the pressure in the system, which will lead to rupture of the housing and an instant loss of oil pressure with all the ensuing consequences.

There is an opinion that expensive synthetic oils allow you to extend drain intervals, but this is a misconception. Even the best quality oil Mobil 1 or Shell Helix loses its properties and becomes contaminated with wear products. Therefore replacement frequency must be strictly observed, especially in urban environments with frequent downtime in traffic jams.

Air Filter: The Breath of Your Engine

The second most important element, which is often changed in conjunction with oil, is the air filter. An internal combustion engine consumes enormous volumes of air, and if it is not cleaned of dust, sand and fluff, abrasive wear of the cylinders will begin very quickly. Dirty filter creates resistance at the inlet, which leads to an enriched fuel mixture, excessive fuel consumption and loss of power.

You can visually assess the condition of the element by removing the housing cover. If the paper has acquired a dark gray or black tint, and the folds are stuck together due to dust, the element requires urgent replacement. In some cases, for example, when using nuleviks (zero resistance filters) with impregnation, they can be washed with a special composition, but ordinary paper filters disposable. For turbocharged engines, air cleanliness is critical, as dust can damage the turbocharger blades.

The frequency of air filter replacement depends on operating conditions. In megacities with dirty air or in rural areas with dirt roads, it should be changed more often than required. Modern engine management systems such as VAG Group TSI or Ford EcoBoost, are sensitive to the readings of the mass air flow sensor (MAF), which can become contaminated with dust if the filter is faulty.

• 🌬️ Reducing intake resistance improves acceleration dynamics and engine pickup at low speeds.
• 💰 Fuel savings with a working filter can reach 5-10% in a combined cycle, which is noticeable for your wallet.
• 🛡️ Protection of cylinders from abrasive wear is the main function that extends the life of the piston group.

Cabin filter: health of driver and passengers

Although the cabin filter does not directly affect engine performance, it is often changed during scheduled maintenance for convenience. This element purifies the air entering the cabin through the ventilation and air conditioning system. Carbon filter is capable of trapping not only large dust and pollen, but also harmful gases such as nitrogen and sulfur oxides, as well as unpleasant odors from the exhaust gases of cars in front.

If the filter is severely clogged, the performance of the air conditioning system will decrease, the windows may fog up due to poor air circulation, and a musty smell will appear in the cabin. In advanced cases, bacteria and mold begin to multiply on the filter, which can provoke allergic reactions in passengers. It is recommended to change it at least once a year, or better yet, every 10-15 thousand kilometers.

When choosing, you should give preference to multilayer models with activated carbon. They are not much more expensive than regular ones, but provide a significantly higher level of comfort. In premium cars such as Mercedes-Benz E-class or Audi A6, complex ionization filtration systems are often used, where replacing the element requires care.

Fuel filter: protecting the fuel system

The fuel filter is another important element that must be replaced, although less frequently than the oil. It purifies gasoline or diesel fuel from water, paraffin (in winter) and mechanical impurities. For modern direct injection systems such as GDI or FSI, the purity of the fuel is critical, since the injectors operate under enormous pressure and have microscopic gaps.

Filters can be remote (located under the bottom or in the engine compartment) or submersible (located in the tank along with the fuel pump). Remote filters are changed more often, usually every 30-60 thousand kilometers. Submersible ones are often assembled with a pump module and are designed to last a lifetime, but in conditions of poor fuel quality it is also recommended to change them or clean the mesh.

A clogged fuel filter leads to a drop in pressure in the rail, which causes loss of traction, engine tripping and starting problems. In diesel engines, water that gets through a poor-quality filter can cause corrosion of the injection pump plunger pairs, the repair of which is very expensive. Therefore fuel quality and the filter state are directly related.

Filter type	Replacement interval (km)	Consequences of ignoring	Replacement cost
Oily	10 000 - 15 000	Wear of liners, turbine	Low
Air	15 000 - 30 000	Excessive fuel consumption, cylinder wear	Low
Salon	10 000 - 20 000	Allergies, glass fogging	Average
Fuel	40 000 - 60 000	Failure of injectors, pump	High

Particulate filter (DPF/FAP) and catalyst

In modern environmental standards Euro-5 and Euro-6, a particulate filter is a mandatory element. It captures particulate soot particles from exhaust gases. Although it is not changed at every oil change, it requires special attention and periodic regeneration. If the engine is not running correctly (for example due to old oil or faults), the diesel particulate filter can quickly become clogged.

A clogged particulate filter creates high back pressure in the exhaust system, which leads to loss of power and overheating of the engine. In some cases, forced regeneration through a diagnostic scanner or chemical flushing is required. Removing a filter software or physical means is illegal in many countries and is harmful to the environment, although it is practiced by owners of old cars.

The catalyst, located in front of the particulate filter or separately, also acts as a filter, but for harmful gases. It converts toxic substances into less harmful ones. If you use low-quality oil with a high content of phosphorus and zinc or bad gasoline, the catalyst can be destroyed and its crumbs can enter the engine, causing serious damage.

Can the oil filter be washed and reused?

No, the oil filter is a disposable item. Washing with kerosene or gasoline will not restore the paper throughput and the properties of the bypass valve. Repeated use guarantees rapid engine failure.

Practical advice on replacement and selection

When choosing filter elements, it is important to focus not only on the car brand, but also on the manufacturer of the filter itself. Often the same parts are produced by companies Mann-Filter, Mahle, Bosch or Filtron for different brands of cars. Buying an original in a beautiful box with the automaker’s logo often means overpaying for the brand, since the same one will be inside Mann, but more expensive.

When replacing the oil filter yourself, you must lubricate the rubber sealing gasket with new oil before tightening it. This will ensure a tight seal and allow you to easily remove the filter at the next maintenance. The filter should be tightened by hand, without using wrenches, so as not to damage the gasket and housing. The tightening torque should be moderate.

After changing the oil and filters, be sure to check the oil level with a dipstick and make sure there are no leaks. Start the engine, wait until the oil pressure light goes out, and turn off the engine. A repeated check after 5-10 minutes will show the real level, since the oil must fill the new filter and the channels of the lubrication system.

⚠️ Attention: When replacing the fuel filter on diesel cars, be sure to remove air from the system (pump the fuel). Air entering the Common Rail fuel rail can lead to water hammer and destruction of the injectors.

FAQ: Frequently asked questions

Is it possible to change only the oil and leave the old filter?

Absolutely not. The old filter contains about 100-200 ml of dirty oil and accumulated dirt. Mixing fresh oil with waste and dirt from the filter will immediately reduce the life of the new lubricant and may clog the new filter with wear products from the old one.

How often should you change your air filter?

Official regulations often indicate 30-45 thousand km, but in the real conditions of a metropolis or dusty area it is better to change it every 15-20 thousand km, preferably along with every second oil change.

Does the filter brand affect engine performance?

Yes, cheap analogues may have low throughput or poor valve sealing. This leads either to oil starvation (if the filter becomes clogged) or to the engine running on unclean oil (if the bypass valve opens).

Does the drain plug o-ring need to be replaced?

Preferably. Aluminum washers soften and may not seal properly when reused, causing oil leakage. Plastic plugs are replaced entirely.