Can I Use 5w30 Instead Of 5w20? (Here’s What Happens)

Whether to use 5w30 rather than 5w20 is a simple concern yet complex. Let me explain why, 5w30 was traditionally recommended in old engine automobiles.

Alternatively, manufacturers recommend light engine oils like 5w20 for modern cars since they have fuel injectors and higher technology, so it works better.

Are you still wondering if you can use 5w30 instead of 5w20?

I would say no. It is not recommendable, although both oils have a winter rating of 5. Still, 5w30 has a higher viscosity or thickness while 5w20 is a bit light, so it has a lower viscosity than 5w30, implying that your car’s engine will be at risk when you use oil of higher viscosity.

Do you still want to understand this subject in detail?

Read on!

Can I Use 5w30 Instead Of 5w20?

The short answer is no.

Even though 5w30 and 5w20 have an equal winter rating of 5, their viscosity is different, and 5w30 is thicker than 5w20. So, if you use 5w30 instead of 5w20, you will be risking your engine because of using oil of high viscosity. Also, the internal parts of the engine are meant to function with 5w20 motor oil.

Oil ratings like 5W30 or 5w20 show the motor oils viscosity index. Therefore, you determine the viscosity rating of any oil by its resistance to flow at some temperatures. If the oil is of high viscosity, the oil is likely to flow slower.

Thus, some engines will use lower viscosity oil to reduce oil flow resistance and increase efficiency in cold weather . However, higher viscosity lubricants are useful in protecting engines at higher temperatures.

So, if you want to know the best oil for use, check the owner’s manual; the manufacturer gives detailed information on the right motor oil. It also includes the oil viscosity rating for most automobiles.

Therefore if there is no substitute for 5W-20 listed in the owner’s manual, using the wrong oil might void the vehicle’s power warranty.

To answer your question; about whether you can use 5w30 rather than 5w20, the answer is no; it may harm your engine in the long run.

What is 5w30

5w30 is a motor oil commonly useful in diesel and light-duty petrol. Its viscosity ranges from a lower grade of 5 to higher viscosity of 30; thus, it is a multi-grade, just like most oils on the market recently.

“W” represents winter, and the number before it stands for viscosity in a lower temperature; thus, the “W” and the number that follows the “W” show viscosity or thickness at very high temperatures when your engine is working.

Therefore, 5w30 will have a winter rating of 5, which means when you compare it to, for example, 10w30, the 5w30 will be less thick because the other oil has a winter rating of 10.

This is to say, it can work in lower temperatures as low as -300C and also can function at higher temperatures as high as 350C. So, if you are in a place of higher seasonal temperature changes, 5w30 oil is a perfect choice.

This multi-grade oil is also suitable in hot climatic conditions because it does not break down easily in high temperatures, ensuring engine protection.

Additionally, if you want oil suitable for vehicles in a cold climate, 5w30 is great. It flows faster when you start your engine in lower temperatures and coat the engine’s internal parts hence protecting the engine.

It is also a perfect choice if going for longer trips that will need more fuel consumption and which have much heat exposure.

Why is 5w30 so Common?

The reason 5w30 motor oil is popular is that it is suitable for various car types and engines.

Its viscosity or thickness range indicates that it is perfect for sealing, lubricating, and protecting the engine’s internal elements in various climate types.

So, the oil’s ability to work in winter and summer saves you the trouble of changing oil weights in different seasons. Since 5w30 has a lower viscosity, your vehicle’s oil pump is not straining, thus ensuring good fuel economy.

5w30 is incredibly versatile, so you can use it in different engines and different ranges of weather conditions.

Therefore, 5w30 is very popular because if you drive a diesel engine or higher duty petrol, you can use it since it flows easily during winter.

Additionally, this oil maintains a safer thickness during summer and works perfectly.

What is 5w20?

5w20 is a type of motor oil that is commonly used in vehicles. It is a light weight oil that helps to improve fuel economy and provides excellent protection for engines. This type of oil is typically recommended for use in cars that have smaller engines.

This motor oil popularly suitable in colder regions. The number 5 before the “W” shows the oil’s thickness or viscosity rating during winter (W), and the number “20” after the “W” represents a 20-weight oil in warmer weather.

5w20 is great in lubricating the engine as if it were a 20-weight oil. Since it is thinner, 5w20 works well in freezing or colder temperatures since it does not have much friction while flowing to deeper engine parts.

Oil viscosity increases with the number, so 5w20 will flow easier and more freely than 5w30.

In colder climates, a thinner oil helps lubricate the engine parts and start. 5w20 thus has good fuel efficiency and performance in colder areas because of its lower viscosity.

However, when your car’s engine reaches average operating temperatures, 5w20 loses the viscosity for protecting the engine parts with time; hence 5w30 will do better, so it is preferred.

Alternatively, 5w20 disintegrates faster in hotter temperatures exposing your vehicle’s engine components to wear out.

The viscosity of 5w20 has a rating of 8.9 at 1000C, while 5w30 has a rating of 11.0. At 400C, the 5w20 rating is 49.8, and the 5w30 rating is 61.7.

What is it best for?

As 5W-20 is a low viscous oil, it is suitable for vehicles driven often in colder regions. It is recommended for light-duty gasoline and diesel engines and can assist with engine sludge and wear issues.

In addition to its remarkable cold temperature properties, 5W-20 oil helps in the following:

  • It improves engine starting performance because the oil flows more readily from the oil pan to  engine at low temperatures, it improves engine starting performance.
  • Its lower viscosity reduces friction and drag on engine components such as the pistons and the crankshaft. This saves energy and reduces oil consumption and improves fuel economy.
  • Its decreased energy consumption reduces exhaust pollutants and improves fuel efficiency.

Despite these advantages,  only use 5W-20 oil if your car manufacturer and recommends it. Using the incorrect motor oil can result in significant damage to the engine and impair its performance.

5w30 versus 5W20 Oil

Although 5w-30 and 5w-20 are popular motor oils in automobiles, there is so much uncertainty about them which makes some people confused.

The viscosity of these motor oils is a significant variation between the oil grades. Due to their viscosity difference, these oils are suitable in various circumstances.

Let’s look at the differences between 5w30 and 5w20;

1. Performance

5w30 and 5w20 are suitable and effective in their respective climatic conditions. If you require a thicker oil to withstand the increased heat in hotter locations, 5w30 is a perfect choice. The engine is likely to heat, so high viscous oil is needed.

On the other hand, 5w20 is suitable in cooler conditions because it has a lower viscosity, so there is less friction in the engine parts, making the engine start faster. 5w20 performs best in cooler weather and ensures good fuel economy.

5w30 is also best for the overall protection of your car’s engine components.

2. Fuel Economy

The 5w30 oil’s viscosity reduces at higher temperatures and allows smooth circulation via the engine parts.

So, 5w30 lowers horsepower and reduces the efficiency of fuel. However, 5w20 has higher fuel efficiency and is suitable for working in cold weather.

3. Operating Temperature

In cold climatic conditions, 5w20 works well, so it is suitable. 5w20 goes fast and efficiently to internal engine parts with less friction, allowing the vehicle engine to start quickly.

At the same time, it helps lubricate the engine components.

 In hotter climates, on the other hand, 5w30 is effective. 5w30, it does not thin out rapidly when left to heat. Thus, at average functioning temperatures, 5w30 is best for improving the overall protection of engine parts.

Is 5w30 Thicker Than 5w20

In colder temperature conditions, 5w20 has a weight of 5, while in warmer weather, it has an oil weight of 20. So, its thickness or viscosity is lower than 5w30.

In the winter, 5w30 has a viscosity rating of 5, but in the summer, it has a greater oil weight of 30, making it thicker.

The primary function of motor oil in the engine is lubricating the metal parts so that they do not rub against each other, leading to friction.

The lubricant helps to keep the engine cool, fills the piston, and protects engine parts from corrosive elements like water. It also helps to remove silicon oxide and acids from engine parts.

The viscosity of the motor oil is a vital component in all of these functions.

The thickness, resistance of oil flow, and functioning at severe temperatures can be described by its viscosity.

Therefore, the thicker the oil is, the higher the viscosity number.

However, if you want the most suitable motor oil for your car, check on the bottle of every type of motor oil; it has a rating indicating the oil kind best for your car.

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Here is a summary of their differences in a table;


5W30 Oil

5w20 oil

Weight The viscosity during the winter is represented by the number 5 before the W. In hot areas, 30 shows the weight of the oil, meaning it has more weight. The viscosity in winter is shown by the 5 before W. In hot areas, 20 represents the weight of the oil, meaning it is lighter and thinner.
Engine Performance In chilly areas, the car engine starts slowly. Allows the car engine to start more quickly in colder climatic conditions.
Viscosity It’s thicker, and due to friction, it moves slowly. Thinner hence less viscous; since there is minimal friction, it flows faster and uses less effort.
Exposure to high temperatures  It does not break down easily in high temperatures, ensuring engine protection. It degrades faster when exposed to a higher temperature and makes the engine components wear out.
Suitable Climate Best used during hot climates or in summer. Most preferable for winter
Fuel Efficiency  It has lower fuel efficiency and does not do well in cold weather. It has higher fuel efficiency and does better in cold weather.

What Happens if you use 5W-30 Oil Instead of 5W-20?

Your car’s engine is designed and optimized to operate with a specified oil grade. Internal engine parts may be damaged if 5W-30 oil is used instead of 5W-20 if the latter grade is recommended by the manufacturer.

In addition, your engine could experience lower fuel efficiency and horsepower.

Final Thoughts

When motor oil has a low viscosity number, it implies that the oil is thinner and flows rapidly.

Alternatively, if the viscosity number is high, the oil is thicker, meaning it is viscous and works best in extreme climatic conditions. Therefore oil with lower viscosity is suitable in cold areas, and oil with high viscosity is perfect for warm regions.

So, can you use 5w30 instead of 5w20? The simple answer is no. As indicated earlier, 5w20 is thinner and flows faster while 5w30 is more viscous or thicker hence perfect for hotter climatic conditions.

In cold climatic conditions, 5w20 works well; it goes fast and efficiently to internal engine parts with less friction, allowing the vehicle engine to start quickly. However, 5w30 does not thin out rapidly when left to heat and due to friction it moves slowly.

Please note that using the wrong oil for your car may harm your engine in the long run.

Therefore, if you are not sure of the best oil for your car, you can always refer to the instructions on the owner’s manual and pick the most suitable oil.

The manufacturer gives detailed information on the right motor oil which includes the oil viscosity rating for most automobiles.


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