5w40 VS 15w40 Engine Oil: Which is Better?

Between 5w40 and 15w40, Which is the best oil for engines? This can be mysterious for many drivers. We know choosing the best engine oil for bikes, trucks, and cars is very concerning to drivers.

Mainly, in today’s market, you can find different types of engine oil that give you many choices. However, if you want to know which lubricant is most suitable, please read this article attentively.

This article is about 5w40 and 15w40 both are the famous motor oil in the market. Nevertheless, before knowing their difference, you should understand what 5w40 and 15w40 are. Below we discuss this in detail. So let’s start.

What Is 5w40?

What Is 5w40

To know about them very well, we should know about each of the characteristics of lubricants. First of all, we will discuss 5w40 engine oil which is best for gasoline and diesel. Typically, users will prefer this oil for their recent car engines and warranty.

5w40 Engine Oil Characteristics: 5w40 engine oil comes with some excellent characteristics. For example:

Adequate for leaded and unleaded gasoline engines. Low viscosity turns into product service life—the reliable oil quality under temperature conditions.

Fulfill several quality oil testing standards. Specifically, it’s not an expensive liquid; that’s why it can fulfill everyone’s needs.

What Is 15w40?

What Is 15w40

We will now talk about the 15w40 engine oil, a multigrade lubricant. 40 implies the viscosity grade of 15w40 motor oil. Besides, the symbol (W) before the number helps you calculate the conditions at which this lubricant can flow.

In particular, to define the temperature level from the previous W index, subtract 30°c. Accordingly, at 15° C temperature, you can use this engine oil.

Generally speaking, for this 15w40 engine oil, its viscosity temperature can be 15°c in the winter. And, at an adequate operating temperature, 5w40 oil density is 40.

5w40 VS 15w40 Motor Oils: Comparisons

5w40 VS 15w40 Motor Oils Comparisons

To understand the characteristics of 5w40 and 15w40, let’s investigate the differences between 5w40 and 15w40:


Viscosity or density is a parameter that implies stickiness, consistency, and flow.

5w40 can survive at 5° of heat with maximum flowability and poor temperatures in winter.

Meanwhile, the motor oil of 15w40 multigrade oil can work well at low and high temperatures with a 15° c.


In terms of availability and rate, 15w40 motor oil has numerous benefits. It’s because it is a prevalent multigrade oil. Even so, this product comes at a reasonable price.

On the other hand, 5w40 is a natural base engine oil and entirely rare.

Often it’s unavailable or has to be synthesized from another lubricant sector. For this reason, this type of product is quite expensive.


Suppose you can find 5w40 crude oil that doesn’t present detergent. That means it has multigrade lubricants of available components.

Temperature Limit:

Now, we will talk about the critical temperature. Both of these products come with different limit temperatures. To determine their heat level, you can depend on the index before the symbol of W.

Especially, 5w40 will start with a 25° C temperature. Under 15° weather conditions, using 15w40 oil is ideal.

5w40 and 15w40: Which Engine Oil Is Best?

Indeed, we know you are very interested to know about 5w40 and 15w40: Which engine oil is better?

It’s not easy to say precisely which oil is the best. Undoubtedly, 5w40 and 15w40 oil styles come with self advantages and suitability.

Additionally, it would help if you used both of this oil depending on various car models and climate conditions. Thus, it’s tough to say which is more terrific between 5w40 and 15w40.

Ideally, if you follow your car manufacturer’s recommendations, It would help. They can help you ideally with which oil is best for your vehicle, motorcycle, or car.

Likewise, you have to be alert to the climate conditions of your living place. In low temperatures, the 5w40 oil works better.

In contrast, you can use this 15w40 oil in normal conditions. Yet, choosing engine oil as well as choosing gear lubricant is essential.

Can I Use 5w40 Instead Of 15w40?

Can I Use 5w40 Instead Of 15w40

Yes, you can use this 5w40 instead of 15w40. You can use this 5w40 instead of 15w40 without any worry. The engine will not damage if the engine oil is slightly thicker than cold.

Adequately, 5w40 oil can be very thick when it’s hot. Nonetheless, before selecting the proper motor oil for your car, you must follow the manufacturer-recommended viscosity grade.

However, many engines need a particular viscosity to perform the engine adequately. That’s why it’s best to use your manufacturer’s recommended motor oil.

5w40 VS 15w40 Temperature Ranges

5w40 and 15w40 main differences refer to how well they help engines considering their utilized temperature. Consequently, in -20°C or -4°F temperature range, you can transform this 15w40 motor oil +40 °C or 104 °F.

On the contrary, you can use the 5w40 temperature range in -22°F or -30°C and 104°F or +40°C. It’s simple to understand that you can use 15w40 in warmer conditions and 5w40 in colder conditions.

Furthermore, 15w40 oil is suitable for motors that run more than 60.000 miles. This is because it can protect the engine better than a broader range of use.

Usually, some oils used are only suitable for winter and summer. Only the second number indicates the summer, and the letter of W indicates the winter.

6.0 Powerstroke 5w40 VS 15w40

6.0 Powerstroke 5w40 VS 15w40

6.0 Powerstroke engines conclude high loads, mainly when driving in severe climates or mountainous terrain. High-quality full synthetic oil can protect these types of loads.

During hot weather, these types of oil have a high density. Plus, during colds, this type of oil has good fluidity. In terms of density and viscosity, 5w40 is the best oil for 6.0 Powerstroke 15w40.

We have considered using synthetic oil instead of traditional oil because of its excellent viscosity, density, and low decomposability.

Notably, synthetic oil doesn’t need regular changes. Even so, it can stay more active after riding 10,000 miles, also old cars.

Though 5w-40 oils are suitable for winter, you can use them in any season.

5w40 VS 15w40

Well, for 6.0 Powerstroke engines, it’s a good idea to use 5w40 oil. The reason is that 5w40 oil works well at the temperature of cold.

This means if you live in a cold place, using 5w40 is the best choice. Ultimately, this oil gives you a huge advantage when running your vehicles in winter.

The owner’s manual says if you see a temperature under 30 deg, you can use 15w40. But if you live in cold weather, you need to use 5w40 motor oil. To get the best result, you can use 5w40 and 15w40 in one night and see the differences.

Final Thoughts

In summary, 5w40 VS 15w40, which is the best one? We are trying to answer this question very well. We hope you can get your answer very well.

Usually,5w40 and 15w40 motor oil are sometimes changed by car drivers. But, you can change it quickly when you want, and what’s best.

Whatever, the absolute thing is that you follow your car’s manual. From this manual, you can know effectively which motor oil is best for your motor.

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