Difference Between 10w30 and 5w40 (With Table)

10w30 and 5w40 are two different types of motor oils. Motor oil is used to lubricate parts of the engine in a vehicle. It is necessary because engine parts are subject to a lot of friction. Motor oil reduces the possibility of later complications.

10w30 vs 5w40

The main difference between 10w30 oil and 5w40 oil is their viscosity. The higher the number before ‘w’ is, the oil will be thicker at 0°C. So, higher the number, more the viscosity. 5w40 is better to use in cold temperatures than 10w40 oil.

In 10w40, 10 stands for 10°C and ‘w’ stands for winter. This oil functions well and is effective when starting a vehicle when it is 10°C. The number 40 signifies the thickness of the oil when the engine is running. Higher the number, thicker the oil.

5w40 is a comparatively thinner motor oil. 5 stands for 5°C, so this oil is perfect to use when it is 5°C in winter. It is very useful for places with cold temperatures, but not freezing temperatures. The number 40 means that it is thicker than usual oil, and lubricates the engine better.

Comparison Table 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

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.

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 that has 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 normal 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 has the capacity to 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 normal 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 temperature is high. Compared to oils with lower viscosity, it works well in higher temperatures. It may not work very well in lower temperatures and the car might have to overexert or strain itself. 10w30 is useful when it comes to older engines as they need thicker oils.

Main Differences 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 viscous than 10w40 at lower temperatures.
  3. 10w30 is better to use for engines in slightly higher temperatures, and 5w40 is better for engines in colder temperatures.
  4. 5w40 is better useful for vehicles that have older engines, but both can be used for high mileage vehicles.
  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.


Oils that are thicker will not be able to flow well through the engine’s parts. Oils that are thinner will not be able to provide protection for the parts from wearing down. Engines wear down with time and friction, so they need to get oiled. To make a choice between 5w40 oil and 10w30, you will have to consider the temperature of the area where you live. Both of them have passed the API ILSAC GF-5 grading.

The properties of each oil depends on a lot of factors. Also, changing the motor oil for your vehicle is a tricky prospect that needs some careful thought. Two things matter the most; how cold the weather gets in winter and which type of oil the engine manufacturer recommends. To choose the best oil for you, it is good to consult a mechanic if you are confused.


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