Engine Oil Has “Winter” and “Summer” Versions – Are You Using the Right One?
Engine oil replacement is a critical part of vehicle maintenance. Choosing the correct oil for the season is essential, as temperature changes in winter and summer have a direct impact on engine performance and protection. Many drivers are unaware that engine oil requirements vary with seasonal temperatures—let’s break it down.
1. Why Viscosity Matters
One of the most important characteristics of engine oil is its viscosity—the oil’s resistance to flow. Viscosity determines how well the oil can form a protective film on moving engine parts.
• Higher viscosity: Flows more slowly, offers a thicker protective layer.
• Lower viscosity: Flows more quickly, reaches components faster during cold starts.
However, viscosity changes with temperature:
• At low temperatures, oil becomes thicker and flows less easily.
• At high temperatures, oil becomes thinner and loses protection capability.
2. Oil Performance in Different Temperatures
Cold Weather (Winter)
When temperatures drop, oil thickens. This makes cold starts harder and engine wear during startup can double compared to normal conditions.
To reduce wear in winter, choose an oil with good low-temperature performance and lower viscosity—this is commonly referred to as winter oil.
Hot Weather (Summer)
In high temperatures, oil thins out, oxidation resistance decreases, and the oil may degrade quickly. This can cause severe metal-to-metal contact between components. In such cases, higher-viscosity oil, known as summer oil, is needed to maintain adequate protection.
3. Understanding Oil Labels
You’ve probably seen markings like “5W-40”, “5W”, or “40” on oil containers. Here’s what they mean:
• “W” stands for Winter. Oils marked with a “W” are suitable for low temperatures.
• The number before the “W”: Lower numbers indicate better low-temperature flow. For example, 0W works well down to -35°C, while 10W is suitable to around -25°C.
• The number after the “W”: Indicates the oil’s viscosity at high temperatures. For example, 40 means the oil is suitable for up to 40°C, 50 for up to 50°C.
• Single-grade oils (e.g., “40”) are typically summer oils.
• Multi-grade oils (e.g., “5W-40”) work well in both winter and summer, offering all-season protection.
4. Temperature Guide for Oil Grades
| Winter Oils | |
| Grade | Suitable Temperature |
| 0W | -35°C |
| 5W | -30°C |
| 10W | -25°C |
| 15W | -20°C |
| 20W | -15°C |
| 25W | -10°C |
| Summer Oils | |
| Grade | Suitable Temperature |
| 20W | 20°C |
| 30W | 30°C |
| 40W | 40°C |
| 50W | 50°C |
| All-Season Oils: | |
| Grade | Suitable Temperature |
| 10W-20 | -25°C ~ 20°C |
| 10W-30 | -25°C ~ 30°C |
| 10W-40 | -25°C ~ 40°C |
| 10W-50 | -25°C ~ 50°C |
| 15W-20 | -20°C ~ 20°C |
| 15W-30 | -20°C ~ 30°C |
| 15W-40 | -20°C ~ 40°C |
5. Seasonal Oil Change Tips
• In regions with large seasonal temperature differences (especially northern winters), adjust your oil choice according to the season.
• Stick to the same brand and quality grade to ensure consistent protection.
• For extremely cold winters, consider synthetic oils with superior low-temperature performance.
Conclusion:
The difference between summer and winter engine oil is something many drivers overlook. Choosing the right oil for the season is one of the simplest yet most important steps in protecting your engine, reducing wear, and extending the life of your vehicle—especially in climates where winter temperatures drop well below freezing.
