The question of what kind of oil to pour into the engine now worries every car owner, because the life of the power unit directly depends on the quality of the lubricant. The automotive chemicals market is oversaturated with offers, and it’s easy to get confused about markings, approvals and brands. The wrong choice can lead to increased wear of parts, carbon deposits, and even costly major repairs.
Modern engines are becoming more and more demanding on the characteristics of lubricants. Engineers are implementing emission reduction systems, turbocharging and direct injection systems, which impose their own limitations on the chemical composition motor oil. Therefore, blind adherence to the principle “if only it flows” has long since sunk into oblivion, giving way to strict adherence to the manufacturer’s specifications.
In this article we will look at what to look for when choosing a lubricant right now, what viscosities are relevant for modern engines and why old time-tested mineral oils are becoming a thing of the past. You will understand the differences between API, ACEA and ILSAC approvals, and learn to read the can label like a professional mechanic.
Basic selection criteria: viscosity and chemistry
The first thing that catches your eye when choosing is the numbers on the label, for example, 5W-30 or 0W-20. This viscosity grade according to the SAE standard, which determines how thick the oil remains at different temperatures. The number before the letter W (Winter) indicates the behavior of the fluid during a cold start, and the number after it indicates the viscosity at the engine operating temperature of about 100 degrees Celsius.
For modern cars manufactured after 2010, manufacturers increasingly recommend low-viscosity oils such as 0W-20 or even 0W-16. This is due to the need to reduce friction in components to save fuel and reduce emissions. However, pouring too thin oil into an old engine with worn-out clearances is a fatal mistake that will lead to a drop in pressure in the lubrication system.
The chemical base also plays a critical role. Now dominates synthetics, created by chemical synthesis of molecules, which ensures stability of characteristics over a wide temperature range. Semi-synthetics are a mixture of a mineral base and synthetic additives, which is a compromise option for budget engines or cars with high mileage.
It is important to understand that viscosity is not an indicator of quality, but only a physical characteristic of fluidity. A high quality 5W-40 oil may be better than a cheap 0W-20 if it meets your engine's needs. Always check the service book, which states in black and white what viscosity the manufacturer recommends for specific operating conditions.
Tolerance systems: what the automaker dictates
The most important parameter when choosing is the availability of specific approvals from the automaker. This is not just marketing, but the result of long-term tests that confirm that a particular lubricant is suitable for working in the friction pair of a given motor. Ignoring these requirements may result in denial of warranty service.
European automakers such as Volkswagen, BMW and Mercedes-Benz, have developed their own strict standards. For example, diesel engines with diesel particulate filters (DPF) require low ash oils (Low SAPS), designated ACEA C3 or C4. Filling such an engine with regular oil will quickly clog the filter and cause it to fail.
American and Japanese manufacturers often rely on API (American Petroleum Institute) and ILSAC (International Lubricant Standardization and Approval Committee) standards. For gasoline engines, API SP and ILSAC GF-6 classes are relevant, which provide protection against low-speed pre-ignition (LSPI), a problem common in modern direct injection turbo engines.
⚠️ Attention: Never use oils approved for older generation diesel engines (for example, ACEA B3/B4) in modern gasoline engines with catalysts. High levels of phosphorus and sulfur will irreversibly poison the catalytic converter.
When looking for oil on the store shelf, first look for your car manufacturer's logo and corresponding approval code on the back of the canister. If the required approval is missing, but there is an inscription “meets the requirements”, this is only permissible for cars with high mileage, but not for new cars under warranty.
Current trends: Low SAPS and ecology
Environmental standards Euro-5 and Euro-6 dictate their own rules of the game. To ensure that the exhaust gases remain clean and the neutralization systems work for a long time, it is necessary to use class oils Low SAPS (Low Sulphated Ash, Phosphorus and Sulfur). This means low content of sulfated ash, phosphorus and sulfur.
When burned, such oils form a minimal amount of solid residues that do not clog particulate filters or damage catalysts. However, it is worth considering that “environmental friendliness” often comes at the expense of the cleaning properties and durability of the oil film under extreme loads, so it is better to reduce replacement intervals with such oils.
The table below shows the correspondence of popular tolerances and their applicability:
| Standard / Approval | Engine type | Features | Application |
|---|---|---|---|
| ACEA A3/B4 | Gasoline / Diesel | High viscosity, durability | Old engines without particulate filters |
| ACEA C3 | Gasoline / Diesel | Low SAPS, medium viscosity | Motors with catalysts and DPF |
| API SP / ILSAC GF-6 | Gasoline | LSPI protection, fuel economy | Modern turbocharged engines |
| VW 508.00/509.00 | Gasoline / Diesel | 0W-20, green | New VW models from 2019 |
Switching to environmentally friendly oils is not a whim, but a necessity for owners of modern cars. Using the wrong formulation may cause the On-Board Diagnostic (OBD-II) system to illuminate the Check Engine Light due to ineffective emission control systems.
What is LSPI and why is it dangerous?
LSPI (Low Speed Pre-Ignition) is the premature ignition of the fuel-air mixture at low speeds. This phenomenon causes a sudden surge in cylinder pressure, which can lead to destruction of the pistons and connecting rods. API SP oils contain special additives that prevent this effect.
Synthetics, semi-synthetics or mineral water: an eternal debate
The choice of oil base depends primarily on the age of the engine and its operating conditions. Synthetic oils have better fluidity at low temperatures, high thermal stability and excellent cleaning properties. They practically do not burn out and allow you to extend replacement intervals.
Semi-synthetics are the golden mean for engines with mileage from 150 to 250 thousand kilometers. It contains a sufficient amount of synthetic components for protection, but has a denser molecular structure, which helps compensate for the natural wear of gaps and reduce waste costs.
Mineral oils are now rarely used, mainly in retro cars or very simple atmospheric engines of an old design. Their main advantage is their low price and ability to soften old deposits without tearing them off in layers, as aggressive synthetics can do. However, their resource is extremely short, and they need to be changed every 5-7 thousand kilometers.
If you are switching from mineral oil to synthetic oil in a high-mileage engine, pre-flush the system with flushing oil or use a “five-minute”, but be prepared for the fact that leaks may begin through the seals, which were previously held in place by coke deposits.
Group III base oils, obtained from petroleum by deep hydrocracking, are legally considered synthetics in many countries, although their properties are closer to semi-synthetics. Real PAO synthetics (Group IV) are much more expensive, but they also work better in extreme conditions.
Replacement intervals: calendar or engine hours?
Car manufacturers often specify replacement intervals of 15, 20 or even 30 thousand kilometers. These figures are relevant for ideal conditions: driving on highways at a constant speed and moderate load. In reality, especially in city traffic jams, oil ages much faster.
The most accurate method for determining oil service life is calculation in engine hours. An engine idling in a traffic jam exhausts its oil life 3-4 times faster than when driving on the highway. Therefore, for the urban cycle, the recommended replacement interval is 7-8 thousand kilometers, maximum 10.
Factors that shorten oil life:
- 🚗 Frequent short trips (the engine does not have time to warm up, condensation and fuel accumulate in the oil).
- 🌡️ Extreme temperatures (extreme heat or frost).
- 🏎️ Aggressive driving style with high speeds.
- ⛽ Low quality fuel (sulfur and impurities quickly saturate the oil).
Ignoring the actual condition of the oil leads to coking of the piston rings, sticking of hydraulic compensators and wear of the crankshaft liners. A visual check with a dipstick once a week will help monitor the level and color, but only laboratory testing can give an accurate analysis.
☑️ Checking the oil condition
Original or analogue: where does the truth lie?
Buying oil from authorized dealers guarantees authenticity, but is often expensive. The market is full of alternatives that are produced in the same factories (Repackaging) but are cheaper. Large petrochemical concerns such as Lubrizol, Infineum and Oronite, produce additive packages for most brands.
However, the risk of running into a fake when buying in unverified places is huge. The counterfeit may not have any protective properties, which will lead to rapid engine wear. Counterfeits are often made in containers of popular brands, so it is important to check the holograms, QR codes and quality of the canister’s printing.
⚠️ Attention: Buying oil in cheap online stores without certificates or bottled from barrels is a lottery with very low chances of winning. Savings of 500 rubles can result in engine repairs costing 100,000 rubles or more.
If you choose an analogue, make sure that the manufacturer has official licenses to produce oils with the necessary tolerances. Lists of licensees are always published on the websites of automakers (for example, on the Mercedes or BMW website you can find a list of approved oils). The brand may be unknown, but having a license is a sign of quality.
The best choice is oil from a major manufacturer, purchased from an official partner, that strictly meets the approval of your engine, regardless of whether the name of the car brand or the name of the oil company is written on the canister.
Frequently asked questions (FAQ)
Is it possible to mix oils of different brands if you need to top up?
In an emergency, you can add up to 10% of the volume of oil from another brand if the viscosity class and base base (synthetic with synthetic) are the same. However, modern oils have different additive packages that can conflict, so it is better to completely replace the mixture as soon as possible.
Is it true that oil needs to be changed only by mileage, and not by time?
No, it's a myth. Oil oxidizes upon contact with air and accumulates moisture even when the car is stationary. The recommended replacement period is 1 year, even if you have driven only 2-3 thousand kilometers.
Does the octane number of gasoline affect the choice of oil?
There is no direct effect, but the use of low-quality fuel leads to accelerated aging of the oil due to unburnt fractions and products of incomplete combustion entering the crankcase, which requires more frequent replacement.
Do I need to flush the engine when switching to a different type of oil?
If you are switching from high-quality synthetics to synthetics of the same class, flushing is not necessary. Flushing is only necessary when switching from mineral water to synthetic water, when antifreeze gets into the oil, or if it is unknown what was previously filled.