Difference between 5w30 and 5w20 | 8 Basic Comparisons

Engine oils are the core fluid of a car. It helps the vehicle to perform well by maintaining the engine’s life. However, if you already have a car or cars just fascinate you, you probably have seen something like 5w-30, 5w-20, or other similar codes mentioned on the engine’s cap. Before we jump into what these numbers and the letter W placed between represents, let’s sneak into a specific term called Viscosity. 

When we point at fluid’s thickness (whether the fluid is thicker or thinner), we basically indicate the fluid’s viscosity level. The more viscous the liquid, the higher the level of viscosity. Precisely saying, Viscosity is a measurement of fluid’s resistance to flow.

The codes mentioned above are two common oil types that display viscosity ratings. The first part of the numbers includes the letter W, which stands for winter. The first number (5w) that includes a W shows the viscosity rating when it is working in a colder temperature and the second number (30/20) shows the viscosity when it is hot. That means the oil will behave like SAE (Society of Automotive engineers) 5 grade when it’s cold, and the oils will act like SAE 30/20 grade when the temperature is warmer. 

Because there are two different numbers joined together, these types of oil are called multigrade oil. Multigrade engine oils can be used in a wide range of temperatures. 

It helps to keep up with the engine by maintaining the friction between the moving parts and resisting the machine from breakdown.

So, as per core concepts, the oil that behaves like 5 SAE grade in colder temperature and 30 SAE grade in a hot climate is known as 5W30 engine oil. On the other hand, the oil that behaves like 5 SAE grade in colder temperature and 20 SAE grade in a hot climate is defined as 5W20 engine oil. 

So, the difference between 5w30 and 5w20 is in the level of their viscosity and how they behave in various conditions. Still, there is a lot to dig into; you need more information to choose the right one for your car engine.

Comparison chart

Difference	5W-30 Oil	5W-20 Oil
Definition	A multigrade oil with 5 winter rating and 30 warmer rating	A multigrade oil with 5 winter rating and 20 warmer rating
Thickness	Thicker	Winter rating= 5 Hot rating = 20
Viscosity rating	Winter rating = 5 Hot rating= 30	Performs better in colder climates compared to 5w30
Performance in colder climates	Performs less efficiently in colder climates compared to 5w20	Performance less efficiently in a warmer climate than 5w30
Performance in warmer climates	Performs better in warmer climates than 5w20	It gives a higher mileage during colder conditions.
Mileage	It gives higher mileage during hot conditions.	The engine works efficiently during colder climates.
Engine performance	The engine works efficiently during hot climates.	It lubricates optimally and creates less friction during cold climates.
Lubrication and friction	It lubricates optimally and creates less friction during hot climates.	Costs less than kitten foods

What is 5w30 oil?

5w30 is a semi-synthetic or conventional oil type that works better in hot temperatures because it has a higher viscosity rating. In order to ensure the operating temperature, multigrade oil like 5w30 goes through various tests before it gets certified. The cold viscosity rating includes tests that range from -10 to -40 degrees Celcius. And the hot viscosity rating includes tests that range from 100-150 degrees celsius. 

This oil is specifically formulated to handle excess heat and friction in car engines at a higher temperature. As for its thickness, 5w30 needs more time to get thinner as the oil heats up. Therefore, compared to 5w20, 5w30 is preferred for engines or climates that are more likely to heat up faster. 

On the other hand, in comparative colder conditions, 5w30 is less recommended as it tends to freeze quickly compared to 5w20. The engine may also experience hiccups or late start issues because it will take more time to distribute the oil to the engine’s moving parts.

However, when the operating temperature is in a normal condition, as for the higher thickness level, the 5w30 motor oil works better than the 5w20 by keeping up with the lubrication system. It helps the engine to circulate faster by reducing the friction and lubricating the surface between the cylinder and piston. When it comes to mileage, the 5w30 performs better with a high mileage car in warmer climates.

What is 5w20 oil?

5w20 is a partially synthetic or conventional multigrade oil type suggested to use in colder climates. The number 20 after 5w refers to how it behaves in hot temperatures. 5w20 has higher pumpability in colder climates because it has lower viscosity in hot climates. Like 5w30, the 5w20 multigrade oil is tested at similar temperatures to get certified. 

One of the core properties of engine oil is that its viscosity starts to decrease as the oil heats up. For that reason, the engine parts move slower if the oil gets thicker. So, the lower the winter viscosity is, the fewer chances to take time to increase the density. 

Take the example of a liquid that has a higher viscosity, such as honey, as it’s thicker and heavier, and it becomes comparatively tough for you to move your finger beneath the surface. But in a thinner fluid like the water, you can move your finger significantly easier. The same happens with the engine’s moving parts. And if the engine parts cannot get the right environment to move in their required rhythm, they are more likely to break down. 

When the viscosity in hot temperature is lower in 5w20 oil, this type of oil will get thinner in less time as it heats up than other engine oils that have higher hot viscosity. But at a lower temperature, 5w20 will take less time to get thicker as for the lower density. As a result, the engine will get more time to operate at an optimal level. For that reason, engine oil like 5w20 is recommended in colder climates. The 5w20 motor oil works well with a high mileage car in colder weather.

5w30 vs 5w20: which is better?

The car manufacturers recommend specific oil types based on various car engines. As for several personal recommendations of car mechanics, sometimes people use 5w30 in a car engine that recommends 5w20 or the other way round. 

You need to understand this, and if a car manufacturer suggests a specific motor oil type for a particular engine, it has definitely been recommended because that specific oil type worked better during testing. 

When it comes to 5w30 and 5w20, the two types of oils give enhanced efficiency according to the environment. So when it comes to comparison, the 5w30 oil performs better in hot climates than the 5w20. And in cold climates, 5w20 is definitely a better choice. Not to mention, 5w20 is definitely a better choice for fuel economy than 5w30.

Frequently asked questions (FAQs):

Conclusion

The difference between 5w30 and 5w20 is in their level of thickness. The 5w30 is thicker compared to the 5w20. The thicker the oil is, the higher level of viscosity it has. Therefore, an oil that comes with higher viscosity is a better choice for engines in warmer conditions. On the other hand, the oil that is thinner works better in colder conditions.