5w30 vs 5w40 oil Guide + Major Difference between 5w30 and 5w40

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​5w30 vs 5w40, which is the best oil for your car? This article will go through the main difference between 5w30 and 5w40 that way, you can make an informed decision when buying oil for your car. we also wrote an article last week comparing 10w40 vs 5w40, you may read here too.

When it comes to changing car oil, some car owners who need an oil change may just drop off their vehicle at the mechanic shop, with the view that they should know which oil is best for their car. For others, the manufacturer’s manual isn’t the final say when it comes to the type of oil that is most suitable for their car.

However, I believe that changing your car’s oil should strictly be your responsibility. So, you ought to know what oil is best for your engine since it would help ensure the optimal performance of your engine.

5W30 and 5w40 are both great motor oils and in this article, we shall be discussing which of these oils is most suitable for your car type.

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Which oil is the Best 5w30 vs 5w40?| Difference between 5w30 and 5w40

So 5w30 vs 5w40 which should you go for specifically for your car? We will fully elaborate on the difference between 5w30 and 5w40.

But before we dive into the difference between 5w30 and 5w40 oil, lets first consider the importance of choosing the right oil for your vehicle, to begin with.

Related Article: Can a Bad Alternator Cause Low Oil Pressure & Can a Car Run With a Bad Alternator?

​Importance of Choosing the Right Oil

​Choosing the right motor oil helps prolong the engine life of your vehicle. This is because motor oil lubricates your engine parts so that they do not grind against each other which may lead to wear and tear. Using the wrong oil will cause your engine parts to be replaced in short periods.

Ensuring the optimal performance of your engine isn’t just about choosing the right oil, it also requires you to change oil ones in every 3000 to 5000 miles to preserve the engine in top healthy condition. Changing the oil also helps to keep the engine cool.

A regular changing of the oil is essential and helps avoids the issue of having dirty oil which isn’t effective in lubrication and cooling. Dirt’s and different foreign particles are regularly trapped in the oil, hence it necessitates you change and replace the old oil.

You can render your warranty invalid and disqualify your car from any repairs or maintenance just by choosing the wrong engine oil. Thus the importance of choosing the right engine oil for your car will decide whether or not you need to overhaul and change your engine. This is more costly than simply choosing the right oil and changing it as required.

Read Also: Can You Mix Power Steering Fluid WITH TRANSMISSION fluid

Factor to Consider When Choosing Your Motor oil

​Oil Viscosity

​Viscosity is the ease at which liquid flow. The viscosity and thickness of oil are closely related. The thicker your motor oil, the more viscous it is. On the other hand, a thinner oil has a lower viscosity. 5w30 and 5w40 motor oils have the number 5 which is then followed by W, representing “winter”.

Hence, both 5W30 and 5W40 motor oils have the same viscosity in winter, which is 5 and moderately low. This simply indicates that the oils flow at very low temperatures but easier through the engine. This is a good quality of motor oil because very viscous motor oil such as a 20w, will not flow as easily through in low temperatures. This will make the oil unable to be distributed through the engine when it is cold thereby leading to damage and wearing away of the engine.

Watch this video to see more factors to look out for when choosing oil for Your vehicle.

How Weather Affects Type of Motor Oil

Climate and weather plays a major role in determining the type of motor oil that you use for your vehicle. Lower temperatures will demand a lower viscosity. The oil flows easily through the system making certain that the engine is at peak performance. This is why both 5W30 and 5W40 are proper for colder temperatures unlike 10w or 20w oils.

However, high temperatures require slightly higher viscosity, but shouldn’t be too high to affect effective flow. You do not want oil that is too thin and easily flowing as it could have long term negative effects on your car.

So if you want to choose between 5w40 vs 5w30 oil that is not too thin such that it flows easily thereby affecting your car negatively, which should it be?

​5w30 Engine Oil

The most common engine oil in the market is the 5w30 engine oil. This type of motor oil can be used for different types of vehicles and works effectively for a wide range of temperatures. Its versatility makes it popular among car owners although it is more preferred for winter periods even though it can also be used in warmer summers. You Can get this motor oil here

​5w40 Engine Oil

The 5w4o engine oil is not so popular because it is not as commonly used as the 5W30. Using the 5W40 engine oil helps to promote your engine health. This engine oil helps to protect the engine from buildup and sludge, thereby eventually preventing damage. The 5W40 motor oil has the ability to move to all other moving parts fast and is thus effective in greasing the engine. You can look up current pricing for this oil here

​5w30 ​vs 5w40 ​, Which is Better?

​These two engine oils (5W30 and 5W40) are mostly similar in some ways.

  • They are both effective and function well during colder periods thus efficiently lubricating the engine.
  • The oil moves properly through all the parts hence making it easy to rev the engine in cold weather.
  • They are both used for warmer temperatures because the thickness provides the necessary protection for the engine.

The main dissimilarity or difference between 5w30 and 5w40 is the viscosity of both oils in warmer temperatures. ​

The 5w30 is better suited for colder temperatures while the 5w40 is better for warmer temperatures.

Difference between 5w30 and 5w40

By now I am sure you know that there are definitely some major differences 5w40 vs ​5w30 oil and below list are the factors that you can use to differentiate both motor oil.

– Low-Shear-Rate Viscosity for 5w30 and 5w40

The viscosity of 5W40 is from 12.5 to 16.3 mm2/s at 100g, while that of 5W30 is from 9.3 to 12.5 mm2/s at 100g. Both of these motor oils are 5 grade when cold, however, 5w30 oil is 30 grade, and 5w40 oil is 40 grade at operating temperatures. 5w40 has a higher viscosity than 5w30 with higher temperatures in summer, which adds to the proper running of the car.

– Temperature range for 5w30 and 5w40

5w30 is used in temperature ranging from -25°C to 25°C, while 5w40 is used in temperature ranging from -25°C to 35°C.

– High-Shear Rate Viscosity

For working viscosity of 5W40, the high-shear rate is min 3.5 at 150g, while for working viscosity of 5W30, the high-shear rate should be at least 2.9 at 150g. This gives an idea of ​​how much the oil withstands in extreme loads.

– Fuel economy

5w40 has a poor fuel economy compared to 5W30.

– Oil flow

5w40 provides higher pressure than 5W30, but less flow.

– Application

5w30 can be used by different vehicles in a different range of temperatures. However, it is ideal for colder temperatures. The 5w40 is often used in higher mileage engine sand and functions better in warmer temperatures.

– The thickness of 5w30 and 5w40

5W30 is lighter than 5W40, making it have a better fuel consumption.

– Cost: Which is more expensive?

5w30 is more costly than 5W40.


​Choosing the perfect engine oil for your car shouldn’t be an issue. Before you consider choosing between these two motor oils, you should know which oil the manufacturer recommend?” This is vital since it determines your warranty and the engine condition.

Most people opt for the 5w30 engine oil due to its versatility. The 5W30 motor oil has the ability to withstand a high range of temperature, and it is also common and easy to find when compared to the 5W40 motor oil.

Though the 5w40 is not so popular, it is still as effective. You can use it for your vehicle if you find the 5w30 too costly for you.

I hope with this post you were able to see the major difference between 5w30 and 5w40.

So now it is up to you which to get 5w30 vs 5w40.

Please share this post if it helped you.

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