Your car will last a while if you choose the right engine oil brand in the right climates. Many owners fail to take care of this particular issue which causes their cars to break down earlier than expected.
People either change the engine oils themselves or ask some mechanic to change them. However, knowing what to use when is essential in this field.
You might have heard the names 5w20 and 5w30 in the automotive field. They are mainly used as oil for the engine and are quite famous in this field. They play an integral role in the welfare of our car and engine.
So, knowing which one to use and the right differences is quite important if you take care of your car alone or hire someone else to do it.
Key Takeaways
- 5W20 and 5W30 are both types of motor oil used in cars.
- 5W20 is thinner and provides better fuel economy, while 5W30 is thicker and provides better engine protection.
- 5W20 is recommended for newer cars, while 5W30 is recommended for older cars or those with high mileage.
5w20 vs 5w30
The difference between 5w20 and 5w30 is that 5w20 is mainly used in colder climates as it is less dense and flows faster, while 5w30 is mainly used in summers or warm places as it flows slower.

Comparison Table
Parameters of Comparison | 5w20 | 5w30 |
---|---|---|
Viscosity | 5w20 is not as viscous as 5w30. It is originally less viscous. | 5w30 is more viscous when compared to 5w20. It is originally more viscous. |
Friction | 5w20 causes friction less than 5w30 | 5w30 causes more friction when compared to 5w20. |
Suitable climate | 5w20 is more suitable for places where it is cold. | 5w30 is suitable for warmer places. |
Thickness | 5w20 is thinner than 5w30. | 5w30 is thicker than 5w20. |
Flow | 5w20 flows swifter than 5w30. | 5w30 flows slower than 5w20. |
What is 5w20?
One of the superior oils for your engine- 5w20, is best fitted for the cold or winter season. The number ‘5’ refers to the viscosity rating, while the 20 refers to the weight of other oils kept in a hotter climate.
When put, 5w20 helps in engine lubrication, similar to any oil of this particulate weight. It’s a thin oil that causes less friction than other oils.
As it is thinner, it helps to oil deeper and all parts of the engine, which is essential during the cold. Having a flow that is quicker than the 5w30 and 5w20 is quite beneficial when it comes to the cold climate.
Usually, winter seasons or solder regions need some engine oil that helps lubricate different parts of the engine faster. Therefore, 5w20 is extremely popular during the winter as it is thin.
Also, having a viscosity of less than 5w30, 5w20 is more efficient in the winter. The fuel service is far better, and the performance is amazing.
But, the cons of this oil start to show when the climate returns to being normal or hot. The less viscosity starts to have bad effects, and the oil being thinner, runs out. Since the oil runs out, the engine’s parts can get exposed, which can wear down.

What is 5w30?
One of the superior oils for your engine- 5w30- is best suited for normal or warm climates. The number ‘5’ refers to the viscosity rating, while the 30 refers to the weight of other oils kept in hotter climates.
It is a thick oil and is more viscous compared to 5w20. It causes more friction and flows slowly, causing it to drag more.
When used during normal operating situations or summers, 5w30 is preferred over 5w20. Being viscous, it is thicker than 5w20 and protects the engine better.
The oil is thick and does not run out, so the parts of the engine are not left exposed. In the long run, the engine is not worn down.
It is unsuitable for colder climates as it takes a while to lubricate the whole engine. Usually, in colder regions or during the winters, it is not ideal to use engine oil as thick as 5w30.
For this very reason, the efficiency of the fuel will also be less. If you use 5w30 during the winter, starting your engine will take a while.

Main Differences Between 5w20 and 5w30
- Being less viscous, 5w20 can flow faster as compared to 5w30. But, 5w30 is more viscous than 5w20 and hence flows slower than it.
- Because of its viscosity, 5w20 is always recommended for places that are cold or during the winter. On the other hand, 5w30 is more suited for warm places or during the summer. It also works in a normal climate, i.e. in normal operational conditions.
- In colder climates, 5w20 shows an amazing performance. The fuel efficiency is also higher, while 5w30 cannot perform as well as 5w20 in colder climates. The efficiency of the fuel also falls.
- You can start your car or, in this case, your engine faster if you use 5w20 during the cold. However, if you use 5w30 during the cold, your engine will take longer to start or respond.
- During the cold, 5w20 causes less friction and helps lubricate the engine faster. Therefore, it is used in the winter when the engine needs to be oiled. 5w30 is very efficient during the summer times. It is thick, and the engine is protected from heat.

- https://www.sae.org/publications/technical-papers/content/2007-01-3539/
- https://www.iasj.net/iasj?func=article&aId=163962
- https://www.sae.org/publications/technical-papers/content/2000-01-1992/
Piyush Yadav has spent the past 25 years working as a physicist in the local community. He is a physicist passionate about making science more accessible to our readers. He holds a BSc in Natural Sciences and Post Graduate Diploma in Environmental Science. You can read more about him on his bio page.