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5w20 vs 5w30 – Everything You Need To Know

Using the right type of motor oil for your car engine is imperative for keeping it up and running. You cannot get a good return on investment if you don’t take care of your engine. Sure, many car owners take their vehicles to a mechanic for an oil change instead of doing it themselves, but that doesn’t give you an excuse to not educate yourself about what goes on inside your vehicle and have some information regarding the best motor oils for your car. This information is not redundant, and can always come in handy if you find yourself stranded and can’t avail the service of a mechanic.

Changing oil is one of the key car care tasks, which is why we will be doing a thorough 5w20 vs 5w30 comparison since those motor oils work best in both hot and cold temperatures. The Society of Automotive Engineers has a statistical code for differentiating between motor oils based on their viscosity characteristics, starting from low and going high: 0, 5, 10, 15, 20, 25, 30, 40, 50, and 60. The term ‘viscosity’ refers to a liquid’s resistance to travel.

Change motor oil

Liquids that are runny and have a watery consistency are given a lower viscosity value whereas thick and consistent liquids (like honey) are given a higher viscosity value. The numbers 0, 5, 10, 15 and 25 are post assigned with the alphabet W, which stands for “winter”, or low temperatures, not “weight”. Keep in mind that the viscosity measurements of an engine oil change when put under varying temperatures, i.e. the weather.

However, when it comes to kinematic viscosity, the numbers are assigned on the basis of the oil’s ability to travel through a regular orifice, at regular temperatures. The longer it takes for the oil to flow through, the higher the SAE numerical code is, owing to the higher viscosity, which means 5w30 has a higher viscosity than 5w20.

Read more about the difference between 5w30 vs 10w30.


What Motor Oils Do and Don’t Do

Car Engine

Motor oil, just like any grease, helps minimize friction between two surfaces. In the case of a vehicle’s engine, motor oil prevents the moving metal parts from grinding against each other or overheating as the liquids flow through the sump. Besides lubricating, motor oil also helps keep the engine clean by getting rid of any acids and silicon oxide that naturally occur during an engine’s lifespan. These waste materials are within the motor oil. Thus, when you flush motor oil from the engine, the waste leaves with it.

Over time, motor oil breaks down, turning into a "sludge-like" material and thus becomes detrimental to the effectiveness of an engine. This process is natural, though you can slow it down with regular check-ups and proper maintenance. Even though motor oil is critical for your car if you use it properly, yet the best motor oils don’t have the power to prevent the breakdown if you don’t take good care of the engine.

5w20 Vs 5w30 - What’s The Difference?

Difference between 5w20 and 5w30

The key difference between 5W20 and 5W30 motor oil is that the former is thicker or less viscous. When you pour it into the engine, 5W20 oil will create less friction owing to its thinner viscosity, which means it results in less drag throughout the engine parts, such as pistons, valve train, and crankshaft. This provides a partial bump in fuel economy. The runnier nature of 5W20 oil also enables the oil pump to move it from the oil pan all the way to the rest of the engine easily. This makes 5w20 a better choice for car owners who live in colder climates.

On the other hand, 5w30 motor oil is a suitable choice for hotter climates where thinner oils tend to break down under high temperatures. The more viscous motor oil is, the better it will be able to resist the heat and not break down. In this case, 5w30 oil will provide better overall engine protection than 5w20. 5w30 is also one of the most widely used types of motor oils for two main reasons, namely because it works great with a diverse selection of vehicles with different engine types, and the oil also covers a broad range of possible temperatures, but, as explained above, is ideal for warmer temperatures.

5w20 Vs 5w30 - Which Oil Should You Use?

5w20 Vs 5w30 - Which Oil Should You Use?

When choosing the best motor oil for your vehicle, it is important to take certain factors into consideration. Even though there is not much difference in the levels of protection you get from 5w20 and 5w30 motor oils, there is a slight difference in their viscosity. If you live in a hot region, you would be better off investing in 5w30 motor oil since it operates better under high temperatures and will thus provide better engine protection.

However, if you live in a colder climate, you would want thinner oil that will heat up quickly, which means 5w20 will definitely a better option for you. If you live in a region that doesn’t experience extreme temperatures, you can use either of the two oils.


Synthetic engine oils are flexible, which means both 5w20 and 5w30 work equally well to protect your vehicle’s engine despite the climate. But if you still find yourself wondering which motor oil to choose between 5w20 vs 5w30, we recommend you go with 5w30. This is because 5w30 oil has high film and shear strength as compared to 5w20, and also works smoothly regardless of the vehicle and the temperature. But don’t fret too much if you cannot find 5w30 motor oil because the difference is not that significant.

About Jason Trevino

Jason is a talented and advanced author, blogger and auto expert. He is determined in researching thousands of products so as to make it easy for the owners to find the best products. He focuses on giving users better understanding on products they are using and ones they anticipate to buy.