Motor oil 10w30 and 10w40: what is the difference?

Engine oil is a key lubricant that ensures stable and long-term operation of the engine, which performs several functions: reduces friction and wear, inhibits the development of corrosion and oxidation, ensures easy low-temperature starting in winter, removes excess heat, reduces noise and vibration, neutralizes acids, reduces high-temperature and low-temperature deposits in internal combustion engine units. The most important indicator for oil is viscosity, since it affects its ability to effectively lubricate the engine under various conditions. Let's take motor oils 10w30 and 10w40, the difference between which is significant.

Viscosity of motor oils 10W-30 and 10W-40

In the coding 10w30 or 10w40, the main indicator is the viscosity class, which characterizes the ability to form a stable oil film on the surfaces of parts. The film plays an important role in preventing wear, creating a protective layer between the rubbing surfaces. At the same time, the oil must have sufficient fluidity for continuous circulation in the lubrication system, maintaining viscosity stability at high temperatures. Thus, viscosity maintains the optimal thickness of the oil film, ensuring effective lubrication under various temperature conditions.

What do the numbers in oil names mean?

The designation usually includes the letters "W" (winter) and numbers, for example, 10w30 or 5w40. The lower the first number, the more stable and lower dynamic viscosity at low temperatures is provided, thus facilitating low-temperature starting and improving energy-saving properties. The higher the second number, the more stable and optimally high dynamic viscosity at high temperatures, thus ensuring the protective properties of the lubricating film at high temperatures. The choice of the correct viscosity depends on the requirements of a specific engine, its operating conditions and the climatic conditions of the region. This property sets the viscosity-temperature range of engine oil operation, according to which it is possible to select the optimal lubricant for specific operating conditions.

As we can see, the lower the ordinal number, the lower the temperature range. Although the step of degree division is small, however, the selection of the correct temperature range affects the protection of the ICE unit at the moment of cold start.

All-season oils are designed for milder climates and are not suitable for use in harsh continental climates.

10W30 vs 10W40: technical differences

This marking can be given to motor oils with different sets of additives. Therefore, we will analyze only viscosity characteristics, arranging a small duel 10w30 vs 10w40. To form the right conclusions, it is enough to understand the behavior of each type during operation, the final effect on the internal combustion engine.

Viscosity characteristics and their meaning

The first number of both oils is the same - "10W", indicating fluidity and viscosity stability at low temperatures. The difference between 10w30 and 10w40 oils is only in the second numbers. They show what viscosity is on a running engine in the summer. If this number is higher, then the oil creates a thicker film at high temperatures and loads, preventing direct contact of the metal surfaces of the engine components. Thus, 10w30 engine oil will be inferior to 10w40 in the summer or for more southern latitudes of operation. Accordingly, in the winter, it will be exactly the opposite. Lubricant with the right viscosity in extreme operating conditions prevents the mechanism from overheating, has better oxidation resistance, extending service life and maintaining lubricating properties.

Are these oils suitable for your car?

Look at the operating manual of your vehicle. If you do not have one, refer to specialized web resources that provide reliable information on suitable oils for your engine. To select oil, it is recommended to follow the instructions of the equipment developer, since these recommendations can extend the service life of your car.

At winter temperatures down to -25 °C, both types of oil demonstrate similar efficiency. When choosing certain types of oils for your vehicle, you should focus on the climatic conditions of the region and the season in which operation is expected.

Choosing between 10W30 and 10W40: advantages and limitations

When choosing engine oil, be sure to take into account the conditions in which the vehicle is used, as well as the characteristics of the internal combustion engine. 10w30 10w40 there is a difference, since each of them has its own unique, but different viscosity-temperature characteristics.

When and why to choose 10W30?

In areas where the temperature does not rise above +25°C, it is preferable to use 10W-30 lubricant. Under these conditions, engine oil for the engine will provide optimal operation.

Situations where 10W40 may be the best choice

For regions with less severe winters, where the temperature often does not drop below -25 °C, and in summer the thermometer can often go over +30 °C, 10W-40 oil becomes a more preferable option.

10W30 and 10W40: impact on the engine

Despite the difference in their operation in the internal combustion engine units, 10w30 and 10w40 oils have mostly the same performance properties.

Engine durability and protection at different temperatures

The lubricant also acts as a heat sink, traps and removes dirt and deposits, does not aggressively affect seals and prevents gas leaks, softens noise and vibrations. Therefore, the right choice must be made. In areas where weather conditions are cooler, 10w30 engine oil is the optimal choice. In regions where temperatures are slightly higher and the engine is affected by both internal and external heat, it is advisable to give preference to 10w40. This oil option effectively retains its properties even at high temperatures, thereby increasing the durability of the internal combustion engine friction units.

Energy efficiency and fuel consumption

Oil with too high a viscosity can create additional resistance and increase fuel consumption. On the other hand, too low viscosity can lead to insufficient lubrication and increased friction. Selecting the optimal oil viscosity for a specific engine can help improve its performance. Regular oil changes and maintaining it in good condition helps maintain optimal performance.

Conclusion

Now we have figured out the importance of choosing between 10w30 10w40. The difference lies in understanding their differences in viscosity and climatic conditions of use. Both products are all-season. Knowing how each oil works at different temperatures and loads allows us to optimally select a 10w30 or 10w40 lubricant that ensures productive operation and service life of the internal combustion engine, as well as an appropriate level of energy efficiency and economical fuel consumption.