5w30 vs 5w40

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5w30 and 5w40 are engine oils that are preferably used for both petrol and diesel engines. The 5w30 is a multi-graded oil having high viscosity. The numbers mentioned in the name of this oil define the high viscosity of 30 and a low grade of 5.

Similarly, the 5w40 has a high viscosity of 40 and a low grade of 5. Therefore, both the oils are significant in their ways. However, a few minute specifications vary from one another to help you choose one among them for the right conditions.

5w30 vs 5w40

The most impactful and visible difference between 5w30 and 5w40 is that 5w40 has a higher viscosity than 5w30. In general terms, you can consider 5w30 as a better option than 5w40 for its clear numerical difference in viscosity. However, this is the ideal guide for the people who want to get into more technicalities of these two engine oils.

Person looking at his car engine

Follow this 5w30 vs 5w40 article to get more clarity upon these two popular engine oils.

5w30 Specifications

5w30 is an ideal motor oil that is widely preferred for diesel engines and light-duty petrol engines. The W in this motor oil stands for winter that is backed up with viscosity numbers for low to high grade.

As it has a winter viscosity of 5, it means that this motor oil is specific to be less viscous with optimal measures at low temperatures. Moreover, it comes with a hot viscosity of 30, which means it has high viscosity at high temperatures compared to its low-temperature figures. However, it is less viscous than its rival motor oils, making it a better option for both conditions.

Furthermore, you should always use the oil that the vehicle manufacturer prefers. For example, 5w30 is an oil that can function well in temperatures low to -30 degrees Celsius and high to 35 degrees Celsius. Therefore, it is ideal for you to choose this oil if you prefer to drive your car in regions that deal with high-temperature variations.

5w30 oil is well suitable for cold climates and supports free flow, even when you start the engine at low temperatures. Moreover, it intends to protect the internal components of your car engine. Therefore, it is a better alternative than oils with a high hot temperature rating of 10 or 15.

Moreover, it is an ideal pick for you to use in your vehicle to go on longer trips. Long trips expose your vehicle engine to more heat and fuel consumption. Hence, for that, 5w30 is the best pick.

5w40 Specifications

5w40 is crude-based engine oil that is ideal for gasoline and diesel engines. It is mostly used in cars that are still under warranty. In addition, whether your vehicle runs with a leaded or unleaded gasoline engine, 5w40 can be the best bet for your car.

Person looking at his car engine

Also, it has low volatility and reduces the aspects of oil utilization. The thinning resistance of this 5w40 oil is better against heat conditions.

5w40 oil has a low viscosity of 5 for winter conditions, whereas it has a bit higher viscosity of 40 for high temperatures than 5w30. Therefore, 5w40 is one of the most commonly preferable motor oils, suitable for versatile engine types. The viscosity level of this oil intends to protect the internal components by lubricating and sealing them.

Even though it lacks its performance compared to 5w30 at higher temperatures, it is still an optimal pick. The difference is minimalistic, and the efficacy is pretty much the same. It puts a low strain on the oil pump and provides assistance in saving your car’s engine from frequent wear and tear.

Furthermore, this oil will offer you the flexibility of not changing the oil weights every season. Hence, it will promote your engine health and prevent it from sludge build-up. This oil will eventually move to all the moving parts within the car engine and is quite effective for greasing the engine frequently.

5w30 vs 5w40


  • Both 5w30 and 5w40 have the potential to protect the internal components of the engine.
  • They both prevent the frequent replacement of the car’s engine.
  • Both have the same winter viscosity of 5.


  • 5w30 is thicker motor oil compared to 5w40 oil, as it has a higher viscosity than 5w40.
  • 5w30 is better suitable for hot temperatures in contrast with 5w40.
  • 5w30 is expensive in comparison to 5w40.
  • Also, 5w30 is multi-graded oil, whereas 5w40 is crude oil.
Person driving his car on an open road

Major Distinguishing Factors

  • Oil flow to the engine is smooth with 5w30, in comparison to 5w40.
  • 5w40 has a high pressure when ignited within the engine than 5w30 motor oil.
  • The operating velocity of 5w30 is 9.3 to 12.5mm2/s, whereas, for 5w40, it is between 12.5 to 16.3mm2/s.

When To Use 5w30?

It would be best to use 5w30 when the seasonal temperature around the region is highly fluctuating. It means that you can use it for light-duty petrol and diesel engines for both low and high-temperature areas.

When To Use 5w40?

It is advisable to use 5w40, mostly in the winter region. It is because the high-temperature viscosity is not ideal in comparison to 5w30. Therefore, it is evident that you must prefer less expensive motor oil like 5w40 only if you are driving your gasoline or diesel vehicle in a low-temperature region.

Final Verdict

Both the oils are mostly similar in terms of their functionality within the car’s engine. However, the only major difference is in their viscosity that makes one more efficient than another. Therefore, by comparing the versatility of usage in terms of climatic seasons, 5w30 is better for summer and winter climates, whereas 5w40 is an ideal pick for only winter climate.

Even though 5w40 is less expensive in comparison to 5w30, do not let the cost deviate you from the original motive of keeping your car safe in seasonal changes.