10w30 vs 5w40 – Difference and Comparison

What is 5w40 Oil?

5w40 is a multi-grade oil, with the w signifying winter, 5 explaining its viscosity at a low temperature, and 40 indicating its viscosity at higher temperatures or when the engine is running. The temperature range in which this oil can work is an impressive -30°C to 50°C. This motor oil has more viscosity, it is thicker and more resistant to flow at higher temperatures. It is best at 5°C, so it is easier to use the car in colder weather.

The usual motor oil has 30 at the end, and 40 signifies it is much thicker. This way, when the engine is hot, it gets lubricated better than with usual motor oil. 5w40 oil is used for engines with a higher mileage because it is thicker. Parts of the engine that are worn down due to friction and time can be lubricated and move better. In the summer, this oil will be thinner. It could cause the engine to wear down and has lesser lubrication.

What is 10w30 Oil?

10w30 is a multi-grade engineered oil with the properties of two graded oils; the SAE 10w and SAE 30 weighted oil. The number 30 signifies the thickness of the oil at the average engine temperature. The oil will be comparatively thicker in higher temperatures. In cold temperatures, it will be perfect to use. This motor oil can work in the temperature range of -25°C to 30°C. It can endure hotter temperatures and not decrease the quality of the engine’s performance. This oil is ideal for heavy-duty engines as it has a heavier capacity.

10w30 oil is available in synthetic oil, mineral oil and other synthetic varieties. Synthetic oil is the best variant as it works well in average temperatures. It has better fuel efficiency and works with lesser consumption of oil. Compared to oils with higher viscosity, it works the engine better and is thicker when the temperature is high. Compared to oils with lower viscosity, it works well in higher temperatures. It may not work well in lower temperatures, and the car might have to overexert or strain itself. 10w30 is useful for older engines as they need thicker oils.

Difference Between 10w30 and 5w40

  1. 5w40 has a 5°C winter grade, so at lower temperatures, it has less viscosity than 10w40.
  2. 5w40 has a viscosity grade of 40, so it is more dense than 10w40 at lower temperatures.
  3. 10w30 is better for engines in slightly higher temperatures, and 5w40 is better for colder ones.
  4. 5w40 is better for vehicles with older engines, but both can be used for high-mileage cars.
  5. 5w40 can be used suitably for comparatively lighter vehicles, and 10w30 is more suitable for heavy-duty vehicles.
  6. 5w40 has a viscosity index of 176, and 10w30 has a viscosity index of 146.

Comparison Between 10w30 and 5w40

Parameters of Comparison5w40 oil10w30 oil
Viscosity IndexThis has a viscosity index of 176This has a viscosity index of 146
Viscosity at 100°CThe viscosity of 5w40 at the temperature of 100°C is 13.7The viscosity at 100°C temperature is 10.7
SuitabilityIt is better suited for SUVs, passenger cars, light trucks and lighter vehicles as such.This is more suitable for truck engines, bigger SUVs and heavier vehicles as such.
ThicknessThinner motor oil that makes the vehicle’s engine parts easier to moveComparatively thicker motor oil but lubricates the vehicle well.
Sulphated Ash1.3%0.8%
Special usesKeeps the engine from overheating and work it smoothly.Prevents oil leaks, sludge and deposits, reduces consumption of oil


  1. https://www.jstor.org/stable/44643955
  2. https://www.jstor.org/stable/44745985