What filters need to be changed when changing engine oil?

Changing engine oil is a basic maintenance procedure that every car owner knows. However, when buying a canister of fresh lubricant, many forget about the critical elements of the filtration system, without which the new fluid will lose its properties after a couple of thousand kilometers. At best, you simply will not get the full service life from expensive oil; at worst, you will provoke oil starvation or abrasive getting into the rubbing pairs.

The list of required filters depends on the age of the car, engine type and manufacturer regulations, but the basic set remains the same for most modern cars. In this article we will look in detail at which filter elements require attention during scheduled maintenance, why saving on them is detrimental to the engine, and how to choose the right components for your Toyota Camry, Volkswagen Polo or any other car.

Many drivers mistakenly believe that it is enough to change only the oil filter, ignoring the condition of the air or cabin cleaners. This misconception can cost expensive repairs. Let's figure out what exactly needs to be changed in conjunction with the oil in order to extend the life of the power unit.

Oil filter: a mandatory replacement element

No oil change is complete without installing a new oil filter. This is the heart of the lubrication system, which traps wear products, carbon deposits, metal shavings and other solid particles formed during engine operation. The old filter is already saturated with contaminants and its throughput is reduced. If left there, new oil flow will encounter resistance, which may cause the bypass valve to open.

When the bypass valve opens, oil begins to circulate bypassing the filter element. At this moment, the engine gets dirty oilcontaining abrasive particles. This causes accelerated wear of the crankshaft bearings, piston rings and camshafts. Therefore, the rule “if you change the oil, change the filter” is an axiom that does not tolerate exceptions.

Modern oil filters are divided into two main types: classic metal housings (“cups”) and cartridges with a replaceable paper element. The former are replaced entirely, the latter require only replacement of the internal element, although many services recommend changing the body along with the sealing rings to guarantee tightness.

⚠️ Attention: When installing a new oil filter, be sure to lubricate the rubber O-ring with engine oil. A dry rubber can curl when twisted, causing an immediate loss of oil pressure and serious engine failure.

When choosing a filter, pay attention to the presence of an anti-drainage valve. It prevents oil from the filter from flowing back into the crankcase after the engine is stopped. This ensures a rapid rise in pressure upon startup and eliminates engine operation in oil starvation in the first seconds.

Air Filter: The Breath of Your Engine

The air filter is often ignored when changing the oil, considering it a “consumable for later.” This is the wrong approach. The internal combustion engine works like a huge pump, consuming enormous volumes of air. For every 10 liters of gasoline burned, the engine requires about 150 liters of air. If this air is not cleaned, the abrasive dust that gets inside acts like sandpaper on the cylinder mirror.

A dirty air filter creates intake resistance. The mixture becomes rich (lots of fuel, not enough air), which leads to increased fuel consumption, loss of dynamics and the formation of black carbon deposits on the spark plugs and valves. You can visually assess the condition of the filter by removing the housing cover. If light does not pass through the paper, and it itself is gray or black, replacement is necessary immediately.

There are several types of air filters:

• 📄 Paper - the most common, disposable, provide a high degree of purification (up to 99%), but are afraid of moisture and have limited dust holding capacity.
• 🌪️ Zero resistance (Zero) — made of multi-layer gauze soaked in oil. They allow more air to pass through, but they filter fine dust less well and require regular washing and impregnation.
• 💧 Oil (inertial) - found on old equipment, require regular washing and changing the oil in the filter bath.

When changing the oil, it is recommended to check the tightness of the air pipe. Even a microscopic crack in the corrugation after the filter will allow untreated air to enter the engine, nullifying the work of the filter element. The seal must be perfect.

Fuel filter: protection of injectors and pump

The quality of fuel at gas stations often leaves much to be desired, and it is the fuel filter that takes the first hit. It retains rust from the tank, dirt, water and paraffins (in winter). The issue of replacing the fuel filter at every oil change is acute and depends on the design of the car.

On modern cars, the fuel filter is often integrated into the fuel pump module, which is located in the tank. The resource of such an element is long (60-100 thousand km), and changing it at every oil change (every 10-15 thousand km) is economically impractical and technically difficult. However, the situation is different on diesel engines.

Diesel engines are extremely sensitive to water and fuel quality. Fuel filter for diesel (diesel fuel filter) often has a water sensor and a sump. It is recommended to change it strictly according to the regulations, which may coincide with oil change intervals, especially when operating in harsh conditions.

Engine type	Filter location	Recommended replacement interval	Risks of missing a replacement
Gasoline (injection)	In the tank (complete with pump)	60,000 – 100,000 km	Fuel pump overheating, pressure drop
Gasoline (carburetor)	Under the hood / in the engine compartment	15,000 – 30,000 km	Clogged jets, unstable idle
Diesel	In the engine compartment (separately)	10,000 – 20,000 km	Failure of fuel injection pump and injectors (very expensive)

If you notice that the car begins to jerk when accelerating or stalls at high speeds, the fuel filter may be clogged. In this case, its replacement is required regardless of the mileage since the last oil change.

Why are diesel filters more expensive than gasoline filters?

Diesel fuel filters have a more complex design. They must not only trap solid particles up to 2-5 microns in size, but also effectively separate water from fuel, since water in a diesel engine causes corrosion of the precision pairs of the high-pressure fuel pump (HPF).

Cabin filter: driver health

Although the cabin filter does not directly affect engine performance, its condition is critical to the health of people in the cabin and the operation of the air conditioning system. When changing engine oil, many drivers take the opportunity to look under the hood or into the interior and change the oil seal preventively.

A clogged cabin filter is a breeding ground for bacteria and mold. The condensation formed on the air conditioner evaporator gets stuck in the wet paper, creating an ideal environment for microorganisms. This is where the characteristic damp smell comes from when you turn on the stove. In addition, the airflow resistance increases and the fan is overloaded.

There are two main types of cabin filters:

• 🌫️ Regular dust - traps large dust, fluff and leaves. They are cheap, but allow gases and minor allergens to pass through.
• 🌿 Coal — have a layer of activated carbon that adsorbs harmful gases, exhaust fumes in traffic jams and unpleasant odors. It is recommended to choose them for urban use.

It is worth changing the cabin filter at least once a year, preferably in the spring, before the season of active flowering and dust. If you change your oil in the fall, before winter, this is also an excellent time to update the filter so that road reagent dust does not get into the cabin.

⚠️ Attention: When installing the cabin filter, follow the airflow direction indicated by the arrow on the end of the housing. If you place the filter upside down, its efficiency drops almost to zero, and its service life is reduced significantly.

Particulate filter (DPF/FAP) and catalyst

In the context of oil changes, one cannot fail to mention environmental exhaust filters. The particulate filter (DPF for diesel engines, GPF for gasoline) and the catalytic converter are not scheduled consumables at every maintenance, but their condition directly depends on the quality of the oil and its replacement intervals.

The use of oils with a high sulfated ash content (not suitable for engines with particulate filters) leads to rapid coking of the DPF. The ash does not burn during regeneration and permanently clogs the filter honeycombs. Therefore, when changing oil, it is critical to pour a product with approval Low SAPS (usually ACEA classes C3, C4, etc.).

If, when changing the oil, you notice that the engine oil level is higher than normal, this may be a sign of problems with the regeneration of the diesel particulate filter. Fuel flowing into the crankcase during frequent attempts to burn the filter dilutes the oil. In such a situation, a simple oil change will not help - diagnostics of the exhaust system is required.

The catalyst is also sensitive to the condition of the engine. If the engine “eats” oil, its combustion products quickly destroy the precious metals in the catalyst, melting its honeycombs. Regular replacement of high-quality oil and serviceability of the piston group is the best protection for expensive environmental filters.

An integrated approach: a checklist before going to the store

In order for the oil change to be successful and not have to go to the store for a forgotten part a second time, you need to prepare the components in advance. Purchasing filters “after the fact” often leads to the installation of non-original analogues of dubious quality or, conversely, to overpaying at the gas station.

Collect information about your car: year of manufacture, engine size, fuel type and VIN code. This data will help the seller select exactly those filters that are suitable for your modification, since even within the same model (for example, Hyundai Solaris) filters may vary depending on the year of manufacture.

Use the following checklist to prepare for replacement:

• 🛢️ Oil — calculate the volume (usually 3.5–5 liters) + 1 liter for topping up.
• 🛢️ Oil filter - must be replaced.
• 💨 Air filter - change every second time or when visually dirty.
• ⛽ Fuel filter - if it is remote and the deadline according to the regulations has come.
• 🏠 Cabin filter - for comfort, change once a year.
• 🔩 Gaskets — drain plug washer and filter O-ring.

Don't forget about the little things. For example, disposable plastic drain plugs found on some models BMW or Mercedes, require mandatory replacement. It is better to replace the metal plug with the stuck washer entirely, so as not to strip the threads in the pan during the next maintenance.

Can oil and air filters be washed?

Modern paper filters absolutely cannot be washed! Water destroys the paper structure and adhesive layer. There are oiled zero-resistance filters that can be washed with special chemicals, but ordinary “consumables” must only be disposed of.

Frequently asked questions (FAQ)

Is it possible to change the oil more often and leave the old filters?

No, this is a grave mistake. The filter has limited dirt holding capacity. If you change the oil every 5,000 km, but the filter costs 15,000 km, then after 10,000 km it no longer works effectively (it is either clogged or the bypass valve is open). The filter is changed at every oil change.

Does the quality of gasoline affect the need to replace the fuel filter?

Absolutely. At gas stations with bad fuel, the life of the fuel filter is reduced by 2-3 times. If you often refuel in questionable places, change the fuel filter more often than scheduled to protect expensive injectors.

Do I need to lubricate the oil filter threads with oil?

There is no need to lubricate the thread, just clean hands. Only the rubber O-ring is lubricated. Lubricating the threads can cause the filter to stick or, conversely, not tighten due to slipping, which will cause oil leakage.

How often should you change the cabin filter if there is no smell in the car?

Lack of odor does not mean clean. Microscopic dust and mold spores do not always have a noticeable odor. It is recommended to change the cabin filter at least once a year, preferably before the summer season or autumn.

Is it necessary to buy original filters?

The original is always a guarantee of quality, but often it is hidden behind the same manufacturers (Mann, Mahle, Filtron), who sell their products under their own brand cheaper. Buying “no-name” filters is dangerous: the paper can get wet and tear, sending shavings into the engine.