10w40 vs. 20w50 Engine Oil: Differences and Can You Swap Them?

The engines of every vehicle require a specific type of motor oil. Each motor oil varies in terms of its weight and viscosity. 

It is also recommended for a specific type of car with a specific type of motor oil. So in this article, we’ll focus on 10w40 oil and 20w50 oil. Let us get started.

10w40 vs. 20w50 Engine Oil

What Is the Difference Between 10w40 and 20w50 Oil?

We will discuss the differences between 10w40 oil and 20w50 oil based on viscosity, fuel economy, and hot weather. Let us begin.

Viscosity

In terms of viscosity, the 10w40 motor oil means it has ten as weight and forty as a viscosity grade. In the 20w50, it means twenty for weight and fifty for viscosity grade. So for a twenty viscosity grade, it means that at one hundred degrees celsius, it will be half as thick as zero degrees celsius.

Fuel Economy

The 20w50 is not declared as the motor oil that is much better than the 10w40 for high fuel economy. Therefore, if your vehicle is already at two hundred thousand (200,000) miles and you are thinking of changing your oil to 20w50 motor oil, there might not be any improvements in your gas mileage and your vehicle’s performance. However, it will keep your engine running smoothly. 

The 10w40 is also not better than the 20w50 for high mileage. The difference between 10w40and 20w50 is that the 20w50 is thicker than the 10w40.

Hot Weather

The motor oil will behave differently in hot weather if the temperature is cold rather than the high temperatures. In low temperatures, the motor oil will thicken. 

As a result, it will not lubricate properly. Therefore, the 20w50 viscosity grade is made for high-temperature situations, and the 20w50 is for cold temperature situations.

Can I Use 10w40 Instead of 20w50?

The rule of thumb is that it depends on your vehicle. The motor oil that you should be using will depend on your vehicle, the season of your vehicle, and many other factors. For example, using a 10w40 motor oil for your engine requiring a 20w50 can cause damages, especially for an extended period. 

The same will also apply if you will use a 20w50 to a vehicle that needs 10w40. Some mechanics would recommend using 10w40 or 20w50 regardless of what vehicle you are currently driving. But the best choice is to read your owner’s manual and follow what is recommended by your manufacturer.

Accidentally Used 10w40 Instead of 20w50: Is It Ok?

It depends. If your vehicle can be added with 10w40, then you are okay. The 20w50 motor oil is used if the manufacturer recommends it. 

You can also use 20w50 for those engines that are made for high temperatures. There are also some recommendations from other manufacturers that would recommend using 20w50 for vehicles made for low temperatures. So you can use 10w40 motor oil if your vehicle is newer and you are driving it in warm weather.

10w40 vs 20w50 High Mileage

A 10w40 motor oil is recommended to be used for high mileage vehicles. The 10w40 motor oil is more vicious and thicker and thicker oils will help older engines to handle high temperatures and even manage to avoid wear and tear. If the motor oil will be thicker, it will reduce more tear and wear and provide an extension to the life of your engine.

On the other hand, the viscosity level of the 20w50 motor oil is leaning into racing engines and not on high mileage engines. High mileage engines run hot and it needs a heavy and loaded operation.

Which Is Better, 10w40 or 20w50 Oil?

The answer is that it depends. This will depend on your vehicle, your car model, and a lot of many factors. For example, if your engine is made for low temperatures or cold starts, your vehicle will perform better using 10w40 motor oil. 

If your engine is made for high temperatures or warm weather, your vehicle will perform better using 20w50 motor oil. But, again, the rule of the thumb is to stick with what your manufacturer recommends. Guessing will not help you and your engine, so you must ask or consult the expert. 

You also need to note that some of the vehicles made today are made to run on 10w40 motor oil. So if your vehicle is new, you must stick with 10w40.

When should I use 10w40 and when 20w50?

If your vehicle is on the newer side, then the recommendation is that you should stick with the 10w40 motor oil. For those engines that are made for higher temperatures and in war weather, if you do an oil change, you can use 20w50 motor oil so that it will prevent any sludge in your engine. So you should take note that in order for you to do an oil change in any car summer with a 10w40 motor oil or even 20w50 motor oil, then you might not have any problems at all with the sludging as long as you will do an oil change on a  regular basis. 

This will also apply to winter vehicles. But the rule of thumb is that if the recommended motor oil for your vehicle is 10w40 motor oil then you can use it but if your vehicle is recommended with a 20w50 motor oil then you can use it too. 

10w40 vs. 20w50 Engine Oil Differences

10w40 vs. 20w50 Toyota

You will use 20w50 motor oil if you are in a warmer climate. This is because the high temperature will cause the oil to be too thin. This motor oil is a high viscosity oil, and it offers cushion and protection against contact from metal to metal. 

If you are living in warmer regions, then you must also use 10w40 motor oil. This is essential, so remember it. 

So for Toyota, the recommended oil for all Toyota engines is 5w30 motor oils. If you want to use 10w40 or 20w50, you still can, but you might be asking for problems shortly.

10w40 vs. 20w50 Nissan

The 20w50 motor oil is used for warm climates. This oil is a high viscosity oil. If your place is in a more warm or hot region, you can also use 10w40. 

But for Nissan engines, you must refer to your owner’s manual to use either of these two motor oils because the recommended motor oil for Nissan vehicles is 5w30 and 10w30. You can use 10w40 vs. 20w50, but you might attract some problems soon.

10w40 vs. 20w50 Subaru

You must use 20w50 motor oil for warmer climates. The 10w40 is also used for warmer or hotter regions. For Subaru, the recommendation is still on your owner’s manual. 

The most common recommended motor oil for all Subaru engines is 0w20 and 5w30. So if you will use 10w40 vs. 20w50, you can, but it might not do good things for your engine.

10w40 vs. 20w50 Mazda

The 20w50 motor oil must be used for war climates, and 10w40 motor oil is also used for warmer or hotter regions. So to know what is the recommended motor oil for your Subaru, you must refer to your owner’s manual if you can use 10w40 vs. 20w50. 

According to Mazda, almost all their vehicles and SUVs will need 0w20 motor oil. Their lone standout might be used with some 5w30, but there is no mention of using 10w40 vs. 20w50. Again, the rule of thumb is to refer to your owner’s manual.

10w40 vs. 20w50 BMW

You can use 10w40 motor oil and 20w50 motor oil in warmer climates or hotter regions. However, this is not the basis of choosing what your motor oil should be. 

The ideal thing to refer to is your owner’s manual because, for all BMW engines, they are recommending 5w30 motor oil. So using a 10w40 vs. 20w50 might happen if you want to, but it might not be suitable for your engine.

10w40 vs. 20w50 Ford

Using a 10w40 motor oil and 20w50 motor oil is suitable for warmer climates or hotter regions. But it does not mean that you can already use these 10w40 vs. 20w50 if you are in a hot place because the idea is to refer to the recommendation of your owner’s manual. And according to the 2020 ford owner’s manual, almost all of their engines must be using a 5w30 motor oil or 0w30 motor oil.

10w40 vs 20w50 Chevrolet

Use 20w50and 10w40 if the climate is warm and for hotter regions. But the best oil is what your manufacturer recommends. You should always follow what your owner’s manual says. 

For Chevrolet, the recommended oil is 5w20, 5w30, or 10w30 in some engines. And according to the owner’s manual of a 2020 chevy, they would recommend 0w20 motor oil or 5w30 motor oil.

10w40 vs. 20w50 Jeep

The rule of the thumb is to follow what your manufacturer recommends. You can use 10w40 and 20w50 for warm climates and hot temperatures, but you need an expert before using a different oil. 

These oils are not recommended, but you can still use them. However, you need to prepare for possible damages.

10w40 vs. 20w50 Volkswagen

For Volkswagen, their recommendation is only 5w30 and 0w20. However, 10w40 and 20w50 motor oil is used for warm places. 

You can use it, but we do not know of any possible damages in the future. Therefore, it is best to read your owner’s manual.

Summary

In summary, every engine needs specific motor oil. With that, it is essential to know what is the right and recommended motor oil to use for your engine. 

The 10w40 motor oil and 20w50 motor oil is used for warm places, but this is not the basis of what oil should be used. The rule of thumb is to consult an expert or read your owner’s manual for instructions and recommendations.

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My name is Hank, and I've been in the automotive industry for 27 years. I've been working in my own auto repair shop for the last 13 years, and now I want to help you here, on my blog. Let me know if you have any questions. Read more