Scheduled vehicle maintenance is not just a formality written in the service book, but a vital necessity for the longevity of the power unit. Many car owners mistakenly believe that changing engine oil automatically means changing all filter elements, but the real picture is often more complex and depends on the regulations of a particular manufacturer. First of all, attention is paid to the lubrication system, where the quality of cleaning of the working fluid directly affects the life of the rubbing pairs.
Ignoring the timely replacement of consumables can lead to oil starvation, coking of channels and, ultimately, to expensive overhauls. In this article we will look in detail at what filters are changed when changing the oil? mandatory, and which ones can be postponed until the next service visit, based on the technical features of modern engines.
Oil filter: mandatory replacement
The main element of the lubrication system that requires replacement every time the engine fluid is updated is, of course, oil filter. Its task is to retain engine wear products, carbon deposits, metal shavings and other solid particles circulating in the system. If you leave the old filter, about 200-300 ml of used oil will remain in it, which will instantly mix with the new clean lubricant, reducing its service life and cleaning properties.
Structurally, modern filters are divided into non-separable (cartridge in a metal case) and collapsible (replaceable paper elements). When using non-separable models replacement of the housing is mandatory, since the paper loses its throughput and can tear under pressure. In dismountable systems, only the internal element is replaced, leaving the plastic or metal cup on the engine.
It is important to understand that saving on this component is unacceptable. Cheap analogues often have low dirt holding capacity and may not provide adequate filtration under extreme operating conditions.
- 🛑 Detains up to 99% of mechanical impurities in oil.
- ⚙️ Prevents abrasive wear of crankshaft bearings and camshafts.
- 🔄 Requires mandatory replacement every time old oil is drained.
There is a common misconception that a quality oil filter can last two replacement intervals. This is a dangerous illusion: the paper becomes clogged and the bypass valve is activated, releasing unrefined oil directly into the line.
Engine air filter: replacement frequency
Although the air filter formally belongs to the intake system and not the lubrication system, its condition critically affects the quality of engine operation and, indirectly, the condition of the oil. A colossal volume of air passes through the intake system, and if the filter element is dirty, the engine begins to “suffocate,” which leads to an over-rich mixture.
If the air filter is heavily contaminated, the likelihood of dust and abrasive entering the cylinders increases, which causes accelerated wear of the piston group. The products of this wear then enter the oil, contaminating it faster than usual. Therefore the question is what filters are changed when changing the oil?, often includes checking the air element.
⚠️ Attention: If you operate the car in dusty conditions (dirt roads, construction sites), the air filter must be checked at every second oil change, even if the regulations require a less frequent change.
The air filter replacement schedule is usually 15–30 thousand kilometers, but visual inspection is required. If the filter bellows look dark and dense in the light, it must be replaced immediately, regardless of mileage.
- ☁️ Ensures the purity of the air mixture entering the cylinders.
- 📉 Reduces the risk of abrasive getting into the engine crankcase.
- 🌬️ Affects acceleration dynamics and fuel consumption.
Cabin filter and its effect on climate
The cabin filter, or air conditioning system filter, is formally not directly related to engine operation and oil change. However, its replacement is often carried out in parallel with the main maintenance to save time and labor costs for the technician. This element is responsible for the cleanliness of the air entering the cabin, trapping dust, pollen and exhaust gases.
A clogged cabin filter creates additional resistance to air flow, which forces the heater or air conditioner fan to work with increased load. Although this does not affect the engine oil, ignoring its condition can lead to foggy windows and bacteria growth in the air conditioning evaporator.
Many services offer a comprehensive service, where the cabin filter is changed along with the oil, especially if the car’s mileage is a multiple of 10–15 thousand kilometers. This is convenient, but is not a technical necessity for the operation of the internal combustion engine.
Symptoms of a clogged cabin filter
If, when the fan is turned on at maximum speed, the air flow from the deflectors remains weak and there is a musty smell in the cabin, the filter requires immediate replacement. Another sign may be a whistling sound when the fan is running.
Fuel filter: maintenance details
The issue of replacing the fuel filter when changing the oil requires an individual approach, since the resource of this element greatly depends on the type of engine and the design of the fuel system. On modern diesel cars, the fuel filter is a critical component that protects expensive fuel equipment (fuel injection pumps and injectors) from water and paraffins.
On gasoline engines with distributed injection, fuel filters often have a service life of 60–90 thousand kilometers and may not require replacement at each maintenance. However, on diesel engines, especially with the system Common Rail, the filter is changed strictly according to the regulations, which often coincides with the oil change interval or is half of this period.
Failure to replace the fuel filter on a diesel engine can lead to water entering the system, corrosion of the plunger pairs and failure of the injectors, the repair of which is very expensive.
- 💧 Separates water from fuel (critical for diesel engines).
- 🛢️ Detains rust and dirt from the fuel tank.
- 🚗 The resource depends on the quality of the fuel and the type of engine.
For diesel engines, replacing the fuel filter is a mandatory procedure, often carried out simultaneously with an oil change, in order to avoid failure of the fuel equipment.
Filter comparison table and replacement intervals
To systematize the information and clearly understand which elements require attention during each visit to the service, and which can be checked later, consider a summary table. Data are averages and may vary depending on the vehicle brand and operating conditions.
| Filter type | Required when changing oil? | Average resource (km) | Consequences of ignoring |
|---|---|---|---|
| Oily | Yes (100%) | 10 000 – 15 000 | New oil contamination, engine wear |
| Air | Desirable/According to condition | 15 000 – 30 000 | Loss of power, increased consumption |
| Fuel (Diesel) | Often (depending on regulations) | 10 000 – 20 000 | Failure of fuel injection pump and injectors |
| Fuel (Gasoline) | No (usually less often) | 60 000 – 90 000 | Pressure drop in the ramp, tripping |
| Salon | No (optional) | 10 000 – 15 000 | Foggy glass, allergies, odor |
The table shows that the only absolutely required element is the oil filter. The remaining positions depend on the design features of your car and the conditions in which it is operated.
Replacement procedure: checklist and nuances
The process of replacing filters, especially oil filters, requires following a certain sequence of actions and using the right tools. Improper installation may result in engine leaks or damage immediately after starting.
First, you need to warm up the engine to operating temperature so that the oil becomes less viscous and the crankcase drains better. Then the car is lifted on a lift or driven into a pit. It is important to remember safety precautions and use protective gloves.
☑️ Correct replacement of the oil filter
When screwing in a new oil filter strictly prohibited use keys or excessive force. The rubber seal must be lubricated with fresh oil, and the filter itself must be screwed in by hand until it touches the seat, after which another 3/4 turn is made.
⚠️ Caution: Never fill the oil filter with oil before installation on modern turbocharged engines. This can disrupt the lubrication system in the first seconds of startup and lead to damage to the turbocharger.
After assembly, you need to start the engine, let it idle for several minutes and check for leaks from under the filter and drain plug. You should also monitor the oil level, since part of the new volume will be used to fill the filter.
Frequently asked questions (FAQ)
Is it possible to blow out the oil filter and reuse it?
Absolutely not. The paper curtain of the filter has microscopic pores, which cannot be cleaned when blown through, but can be damaged. In addition, old oil remains in the filter, which will spoil the fresh one.
Is it necessary to change the automatic transmission filter when changing the engine oil?
No, these are different systems with different service intervals. The automatic transmission filter is usually changed during a complete transmission oil change, the intervals of which can range from 40 to 100 thousand kilometers.
How often should you change the air filter when driving around the city?
In a megacity with a lot of dust and traffic jams, it is recommended to change the air filter every 15,000 km or once a year, even if visually it looks normal.
Does the quality of gasoline affect the frequency of replacing the fuel filter?
Yes, directly. When refueling at untested gas stations, the life of the fuel filter may be halved due to the high content of mechanical impurities and resins.
What happens if you forget to replace the oil filter?
The new oil will quickly become contaminated with wear products found in the old filter. This will lead to accelerated aging of the oil and increased wear of engine parts, defeating the purpose of the replacement procedure.