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

Choosing the appropriate motor oil for your vehicle is a critical step in keeping it running smoothly. Your engine benefits greatly from the work that your motor oil does. By using a motor oil, you can extend the life of your engine and avoid having to do any repairs. A fluid’s viscosity is its ability to flow. The higher the viscosity, the slower the oil will flow into the engine. Viscosity of oil decreases as temperature rises. Thinner motor oil will be the outcome. These additives will behave like thin oil if added to base oils. We’ll be discussing 5w40 and 15w40 motor oil in this article. Is it possible to interchange 5w40 and 15w40 motor oils? We’ll answer these questions and more. Let’s get this party started now.

What Is the Difference Between 5w40 and 15w40 Oil?

There are some similarities between 5w40 and 15w40 motor oils, but there are also some distinctions. Some drivers are swapping these two motor oils, but most drivers are terrified of the repercussions and do not do so. As a result, we can tell the difference between 5w40 and 15w40 motor oils by looking at their mpg ratings, viscosity in hot conditions, and other characteristics.

Viscosity

The American Petroleum Institute or AOI and the Society of Automotive Engineers or SAE provide a standard for measuring oil viscosity. The viscosity of an SAE 5w40 motor oil differs from a 5w oil in low temperatures to a 40w oil in high temperatures, for example. As a result, the viscosity grade of 5w40 engine oil and 15w40 engine oil will be the same when the engine is running at the same temperature. The thinner one will be, and the lower viscosity grade it has will be, the difference between the two.

Fuel Economy

Motor oil’s economic standing will be determined by its usage and supply in the market. Some engine oils, such 5w40, aren’t always readily available. However, because it is a multi-grade oil, 15w40 motor oil is frequently utilized on the market. You can save money by using the 15w40 motor in a wide variety of engines. As a result, it has a monopoly on the economy. Unfortunately, there isn’t enough information available to compare the fuel economy of the two.

Hot Weather

The 15w40 motor oil has a thicker viscosity than 75% of its weight. This is due to the polymer’s increased weight as it thickens. As soon as it hits 70 degrees Fahrenheit, the 5w40 motor oil becomes a thicker oil with a weight of 40 grams. This frequently has the opposite effect on the general population than what they expect. For example, the general consensus is that heating motor oil causes it to thin out. Generally, yes, but there’s always the matter of polymers to contend with.

Winter is represented by the letter w. Freezing temperatures will cause a spike in the flow rate of engine oil. Oil will be thin if the number is low.

Can I Use 5w40 Instead of 15w40?

Yes, you can use 5w40 motor oil in place of 15w40 motor oil in your vehicle. This is because oil that is less thick than when it is cold will not damage an engine. A 5w40 motor oil, on the other hand, will thicken even more when heated. However, if you’re looking for the best motor oil for your car, you’ll need to follow the manufacturer’s recommendations.

Accidentally Used 5w40 Instead of 15w40: Is It Ok?

Yes, that’s OK. There’s no need to be concerned about major damage or engine failure. The lower the first number, the faster the oil will circulate when the engine is starting up. This is especially true in the winter. This will reduce the amount of wear and tear on your engine with each and every start-up. The viscosity curve flattens in heated locations as a result. Always consult your car’s owner’s manual for the appropriate motor oil and viscosity grade for your vehicle. You’re good to go if it says “both motor oil.” The proper operation of many engines necessitates the use of a specified viscosity. The best advice is to use the oil recommended by your vehicle’s manufacturer.

5w40 vs 15w40 High Mileage

In order to support high mileage engines, mechanics use 5w40 motor oil. A thicker-than-average motor oil is why this is so. It also improved the lubrication of moving parts. Engines with high mileage, on the other hand, may benefit from the usage of a 15w40 motor oil.

Which Is Better, 5w40 or 15w40 Oil?

It is imperative that you follow the manufacturer’s recommendations while looking for the best motor oil for your car. This is an important rule that everyone must adhere to. Because of this, you’ll know exactly how long your car’s warranty will last. It’s also important to note that the weather has a big impact on which motor oil is ideal for your engine. Using the 5w40 motor oil instead of the 15w40 motor oil in a cold climate is a better choice because the 5w40 oil is more tolerant of cold starts and quieter than the 15w40. However, if you live in a location where the temperature rarely drops below freezing, 15w40 motor oil is the best choice.

When Should I Use 5w40 And When 15w40?

Depending on where you live, you may want to use 5w40 or 15w40 motor oil in the winter. Low-temperature engine start-ups benefit greatly from 5w40 motor oil. Temperatures in this range will allow the 5w40 motor oil to flow more smoothly. 5w40 motor oil, however, has a high viscosity and can protect your engine from wear and tear when the engine is operating hot. Using 5w40 motor oil in European vehicles with gas-powered engines is also a good idea.

5w40 vs. 15w40 Toyota

All Toyota engines should be lubricated with 5w30 motor oil. The 5w40 motor oil and the 15w40 motor oil are not recommended for Toyota engines. You can start your engine using 5w40 motor oil because it will flow more easily in cold temperatures. If you live in a cold climate or have an older vehicle, you should use 15w40 motor oil. You must, however, always consult your owner’s handbook for guidance.

5w40 vs. 15w40 Nissan

Nissan automobiles should be lubricated with 5w30 or 10w30 synthetic motor oil. The 5w40 and 15w40 motor oils are not on the recommended list for Nissan engines. You can, however, start your engine using 5w40 motor oil because it flows more smoothly at low temperatures. If you live in a cold climate or have an older vehicle, you should use 15w40 motor oil. However, you should always consult your owner’s handbook for guidance.

5w40 vs. 15w40 Subaru

0w20 and 5w30 synthetic motor oils are suggested for Subaru engines. It is not suggested for Subaru engines to use 5w40 or 15w40 motor oils. You can, however, start your engine using 5w40 motor oil because it flows more smoothly at low temperatures. But if you live in a region where the temperature drops below freezing or you have an older vehicle, 15w40 motor oil is the best choice. You must, however, always consult your owner’s handbook for guidance.

5w40 vs. 15w40 Mazda

0w20 motor oil is required by nearly all Mazda automobiles and SUVs. Their lone bright spot might be combined with a 5w30. The 5w40 oil and the 15w40 oil aren’t recommended for Mazda engines. You can start your engine using 5w40 motor oil because it will flow more easily in cold temperatures. It’s best to use 15w40 motor oil if you live in a region where the temperature drops below freezing or if you have an older vehicle. The best advice is to consult your vehicle’s owner’s manual at all times.

5w40 vs. 15w40 BMW

They recommend 5w30 motor oil for all BMW engines. The 5w40 motor oil and the 15w40 motor oil are not recommended for BMW engines. You can start your engine using 5w40 motor oil because it will flow more easily in cold temperatures. It’s best to use 15w40 motor oil if you live in a region where the temperature drops below freezing or if you have an older vehicle. You must, however, always consult your owner’s handbook for guidance.

5w40 vs. 15w40 Ford

Most Ford engines require a 5w30 or 0w30 motor oil, according to the 2020 owner’s manual. The 5w40 oil and the 15w40 oil aren’t on Ford’s list of recommended lubricants for engines. You can, however, start your engine using 5w40 motor oil because it flows more smoothly at low temperatures. It’s best to use 15w40 motor oil if you live in a region where the temperature drops below freezing or if you have an older vehicle. However, you should always consult your owner’s handbook for guidance.

5w40 vs. 15w40 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 2020 Chevy owner’s manual. Because of this, the 5w40 and 15w40 motor oils are not recommended for use in a Chevrolet engine, respectively. You can start your engine using 5w40 motor oil because it will flow more easily in cold temperatures. It’s best to use 15w40 motor oil if you live in a region where the temperature drops below freezing or if you have an older vehicle. You must, however, always consult your owner’s handbook for guidance.

5w40 vs. 15w40 Jeep

A jeep’s recommended viscosity ranges from 0 to 5W20, 5W30 to 10W30. For a Jeep engine, it is not recommended to use motor oils with viscosities of 5W-40 or 15W-40. You can, however, start your engine using 5w40 motor oil because it flows more smoothly at low temperatures. It’s best to use 15w40 motor oil if you live in a region where the temperature drops below freezing or if you have an older vehicle. To be on the safe side, it’s best to consult your vehicle’s owner’s manual.

5w40 vs. 15w40 Volkswagen

Only 5w30 and 0w20 are recommended by them. The 5w40 oil and the 15w40 oil aren’t on the list of recommended lubricants for Volkswagen engines. You can start your engine using 5w40 motor oil because it will flow more easily in cold temperatures. It’s best to use 15w40 motor oil if you live in a region where the temperature drops below freezing or if you have an older vehicle. You must, however, always consult your owner’s handbook for guidance.

Summary

To summarize, drivers have been known to use 5w40 oil in place of 15w40 oil. If at all possible, try to avoid switching them, as they are interchangeable.

However, you should always check your owner’s manual to see what type of oil is advised for your vehicle. If that is the case, your vehicle’s maker is well-versed in the ideal motor oil.