Let's start with the basics:

What functions does motor oil have in an internal combustion engine?

Motor oil must meet specific requirements to ensure the best performance of the engine. Its main tasks include reducing friction, lubricating the moving parts of the engine, and collecting and removing contaminants and aging products that could damage the engine. Additionally, it neutralizes acids from the fuel, prevents oxidation processes and corrosion, and finally, it cools the engine by dissipating the heat generated by the moving parts.

Main Types of Motor Oils:
The different types of motor oils can be classified based on the composition of the base oil and the additives added to them. There are four main types: mineral oils, semi-synthetic oils, fully synthetic oils, and high-mileage oils.

• Mineral-Based Motor Oils: Mineral motor oils are produced by refining crude oil and offer a cost-effective solution for engine lubrication. The viscosity of mineral oils usually varies over a wide range, and they are suitable for normal operating temperature ranges. However, they are less efficient at extreme temperatures and need to be changed more frequently than synthetic oils.
  
  
• Semi-Synthetic Motor Oils: Semi-synthetic or part-synthetic motor oils consist of a mixture of mineral and synthetic oils. This combination offers better performance and protection than pure mineral oils while remaining more affordable than fully synthetic oils. Semi-synthetic oils are particularly suitable for moderate climates where both cold starts and high heat protection are required.
  
  
• Fully Synthetic Motor Oils: Fully synthetic oil is produced using advanced chemical processes and offers excellent performance in both cold and warm conditions. These oils have outstanding lubricating properties, reduce engine wear, and allow for longer oil change intervals. Fully synthetic oils are especially recommended for modern, high-performance engines that operate at high temperatures and under high loads. These oils also perform well at low temperatures, making cold starts easier.
  
  
• High-Mileage Motor Oils: These oils are particularly used in older vehicles where the engine has already experienced significant wear. They contain special additives that help reduce oil consumption. Additionally, they improve the engine's sealing ability and reduce wear, thereby extending the engine's lifespan.

SAE Viscosity Ratings – The Large Number in the Middle of the Bottle

The classification of motor oil viscosity was developed by the Society of Automotive Engineers (SAE) to standardize the flow properties of oils under various temperature conditions. SAE ratings use numerical sequences that indicate the temperatures at which the oil functions optimally.

The numbers listed in the SAE classification are divided into two main categories: winter viscosity (W) and operating viscosity.

Winter Viscosity (W), also known as dynamic viscosity or cold viscosity: The letter "W" stands for "Winter." The number preceding it (e.g., 0W, 5W, 10W) indicates how well the oil flows at cold temperatures. The lower the number, the better the cold start properties of the oil, as it remains fluid and pumpable even at low temperatures. The starting point of the winter classification is -35°C, corresponding to a 0W oil. Each subsequent step increases the temperature by +5°C: 5W at -30°C, 10W at -25°C, and so on.

Operating Viscosity: The number after the "W" (e.g., 20, 30, 40) provides information about the viscosity of the motor oil at 100°C. The higher this number, the higher the oil's viscosity, and the thicker the oil film in the engine's warm operating condition, providing better wear protection for engine components at high temperatures.

Modern Multi-Grade Motor Oils (e.g., 0W-20, 5W-30, 10W-40) are capable of adapting to a wide temperature range thanks to advanced additive technology. Such oils remain fluid in winter to facilitate cold starts and are thick enough at rising temperatures to ensure adequate lubrication.

In summary, when choosing motor oil, it is essential to ensure that it meets the requirements specified by the vehicle manufacturer. This ensures proper lubrication, cooling, and protection of the engine, which extends the engine's lifespan and ensures high performance. When topping up motor oil, you should make sure that the correct oil type is used and that the oil level is between the minimum and maximum markings. Using the wrong motor oil can, in the worst case, lead to engine damage.