Updated at: 13-03-2022 - By: micdot

While you’re behind the wheel, your car’s engine is also hard at work. A number of moving parts will be present in your vehicle while the engine is running. The friction of the moving parts will cause some wear and tear when these components bump and grind against one another. As a result, the motor oil’s purpose is to lubricate these components in order to reduce their wear and tear as well as the friction that they cause. Of course, a higher-quality oil is required to safeguard a strong engine. Our engines depend on motor oils, thus this is a given.

You should also be aware of the viscosity type of your engine’s motor oil, which is just as important. The base stock for both 10w40 and 10w50 motor oils is the same. Because of this, it’s possible that they’ll be used interchangeably in the future. In this article, we’ll compare and contrast the properties of 10w40 and 10w50 synthetic motor oils. So, without further ado, here we go.

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

A lubricant, such as motor oil, is well-known. Motor oil works by reducing the amount of friction caused by the engine’s moving parts, allowing them to operate more freely and efficiently. Your engine will last longer if you use motor oil to keep it well-lubricated. They will also help keep the engine from overheating by reducing the amount of heat it generates. Because of its good mix of low-temperature flow, shear stability, and many other positive properties, a conventional modern engine will use 10w40 and 10w50 motor oils. However, let’s focus on the contrasts between these two examples.. Viscosity, fuel economy, and hot weather will be used to separate them.


At absolute zero, the viscosities of 10w40 and 10w50 motor oils are identical. It’s well-known that they’re in the same academic group. The 10w50 motor oil has a higher viscosity than the 10w40 motor oil at operating temperatures of 100 degrees Celsius. One hundred sixty is the viscosity index for 10w40 motor oil, and one hundred sixty-seven is for 10w50 motor oil. As a result, the 10w50 motor oil’s viscosity will fluctuate more subtly as the temperature changes. As a result, both of these motor oils will operate similarly at low temperatures.

The 10w50 motor oil, on the other hand, will provide better protection at operating temperatures than the 10w40 motor oil. The 10w50 motor oil is also more difficult to pump than the 10w40 motor oil due of its high viscosity.

Fuel Economy

For engines that require less horsepower, the 10w40 motor oil is typically used in vehicles with a lower output. Since the introduction of 0w20 and 5w20 motor oils, fuel economy motor lubricants have been increasingly popular. The majority of these motor oils will improve fuel efficiency by one to two percent. In order to get the best gas mileage, all you need to know is that oil with a lower viscosity, which makes it simpler to move through the oil system, is lighter.

Hot Weather

When the oil is cold, the thinner it will be the higher the W number on the container. Low-temperature thickening will be more pronounced with a lower number. There is a significant variation between the viscosity of 10w40 and 10w50 motor oils when subjected to high temperatures. While the 10w40 motor oil’s temperature rises, the 20w50 motor oil will not thin out as rapidly, but it can also become too thick in low weather.

Can I Use 10w50 Instead of 10w40?

You can, but only if you follow the instructions in your vehicle’s owner’s manual. For example, a 10w50 motor oil will not provide further protection for a modern car’s engine, which calls for a 10w40. You should always follow the advice of your vehicle’s manufacturer in this regard. Problems can arise sooner when you use a motor oil that is not approved for use by your vehicle maker.

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

It’s fine, you know. If you notice that your car’s oil is causing you problems, you may always have it changed. When the temperature rises, the solid-liquid interface becomes thinner. This means that as the engine heats up, it will also become thinner.

10w50 vs 10w40 High Mileage

It is recommended to use 10w50 motor oil in vehicles with a mileage of at least sixty thousand (60,000) miles. High-mileage automobiles, on the other hand, should use a 10w40 motor oil. Thick oils, such as 10w40, can better withstand high temperatures and even prevent wear and tear on older engines. Thicker oil will save your engine from wearing out as quickly and help it last longer.

Which Is Better, 10w50 or 10w40 Oil?

Oils rated 10w50 and 10w40 have identical viscosities at room temperature. The 10w50 motor oil has a higher viscosity than the 10w40 motor oil at working temperatures of 100 degrees Celsius, despite the fact that they are both in the same class.

When should I use 10w50 and when 10w40?

Between 10w50 and 10w40 motor oils, the difference is in the grade. As a result, the ranges of the numbers forty and fifty are distinct. The only thing that varies is the letter grade. They will both perform the same in a low-temperature environment. The 10w50 motor oil offers higher protection at operating temperatures than the 10w40 motor oil. However, we are not debating which motor oil is the best.

In this article, we’ll go over how often you should change your car’s oil. The solution can be found in the manual that came with your vehicle. The use of these motor oils is permitted only if they are specifically suggested for your vehicle’s engine.

10w50 vs. 10w40 Toyota

All Toyota engines should be oiled using 5w30 motor oil, which is the industry standard. Low-horsepower engines, which often require an oil that flows smoothly at low temperatures, are more likely to utilize 10w50 motor oil. Any temperature above freezing can be used with the 10w50 motor oil. It’s fine to use this oil, however Toyota does not suggest it.

10w50 vs. 10w40 Nissan

Nissan automobiles should be lubricated with 5w30 or 10w30 synthetic motor oil. Nissan does not recommend these two oils, however you can give them a shot if you want. Low-horsepower engines often utilize 10w40 motor oil, which is designed to flow smoothly at low temperatures. If the temperature is above freezing, you can also use 10w50.

10w50 vs. 10w40 Subaru

Subaru engines run best with 0w20 or 5w30 synthetic motor oil. Although 10w50 and 10w40 motor oils can be used, Subaru automobiles are not advised to do so. All temperatures above freezing are suitable for 10w40 motor oil, while 10w50 motor oil is used in engines with less horsepower.

10w50 vs. 10w40 Mazda

0w20 motor oil is required by nearly all Mazda automobiles and SUVs. Their lone bright spot might be combined with a 5w30 lubricant. It is possible to use 10w50 and 10w40 motor oil, although this is not recommended. Engines with less power typically use 10w40 motor oil. High-performance engines and those operating in colder climates need 10w50 motor oil.

10w50 vs. 10w40 BMW

BMW recommends 5w30 oil for all of its engines. Although 10w50 and 10w40 motor oils are not recommended, you can still use them if necessary. Just be ready for any potential damages. More powerful engines and cold temperatures necessitate the use of 10w40 motor oil, whereas engines with lower horsepower require 10w50 motor oil.

10w50 vs 10w40 Ford

A 5w30 motor oil or a 0w30 motor oil is required for nearly all of Ford’s engines in the 2020 owner’s manual. In terms of motor oil, neither 10w50 nor 10w40 are advised. However, you are free to give them a shot if you so desire. Engines rated at less than 100 horsepower should be lubricated with a 10w40 motor oil. High-performance engines and those operating in temperatures above freezing should use 10w50 motor oil.

10w50 vs 10w40 Chevrolet

Some engines in the Chevrolet lineup require 5w20, 5w30, or even 10w30 oil, depending on the model. 0w20 or 5w30 motor oil would be recommended by the owner’s manual of a 2020 Chevy. Although 10w50 and 10w40 motor oils aren’t suggested, you can still use them if you want to. If you have a lower-powered engine, 10w40 motor oil can be used, whereas 10w50 motor oil can be used in any temperature that is above freezing.

10w50 vs. 10w40 Jeep

There are four different viscosities advised for jeep vehicles: zero weight (20w20), five weight (5w30), and ten weight (10w30). In general, the 10w40 motor oil is suitable for engines with a lower horsepower, while the 10w50 motor oil is best suited for motors with a higher horsepower.

10w50 vs. 10w40 Volkswagen

Only 5w30 and 0w20 are recommended. Motor oils with a viscosity rating of 10w50 and 10w40 are not recommended. Motor oils 10w40 and 10w50 are used in engines with low horsepower and at temperatures above freezing.


In summary, winter is the best time to use a high viscosity oil, according to experts. Temperature and whether or not your engine is operating at an ideal temperature have a significant impact on the type of motor oil you should use. Whether or not to use 10w50 or 10w40 motor oil will be determined by a variety of factors. The best way to find your owner’s manual is to go to the website.