5w40 vs. 10w40 Engine Oil: Differences and Can You Swap Them?

Motor oil might be very simple to some people, but it can also get confusing. There can be many different motor oils in the market, and the choices can be overwhelming. These motor oils have different brand names and different types in terms of their application.

This is an essential matter because using the wrong motor oil can damage your vehicle. So now, let us put an end to this confusion. In this article, let us discuss the differences between 5w40 motor oil and 10w40 motor oil.

Both of these motor oils are sometimes swapped by car drivers. So let us know more about the 5w40 motor oil and 10w40 motor oil. Here we go.

What Is the Difference Between 5w40 and 10w40 Oil?

All automobiles need lubrication in their engines. Motor oils act as a lubricant. They lubricate the engine and decrease any tear and wear caused by the engine’s moving parts internally.

Motor oil also prevents any corrosion that can happen in your engine. In addition to that, motor oil will also clean your engine.

With that, choosing the best and suitable motor oil for your vehicle is a vital matter. So now, let us differentiate 5w40 motor oil and 10w40 motor oil in terms of fuel economy, hot weather, and viscosity.

Viscosity

The 5w40 motor oil is thin if you compare it with a 10w40 motor oil. This motor oil is made to seep into the moving parts of the engine. So the number forty means the thickness of the motor oil.

With this, the 5w40 motor oil is thicker than your average motor oil. Therefore, it lubricates any engine better than your average motor oil.

Fuel Economy

Vehicle manufacturers and mechanics prefer to use the 5w40 motor oil for their engines. This is because the said motor oil offers high mileage. This 5w40 motor oil usually is thick if you compare it to most of the other motor oil.

The 5w40 motor oils are also more resistant to heat. So for those vehicles residing in cold temperatures, the 5w40 motor oil is a good pick. 5w40 motor oil can also deliver an excellent pump to your engine even in less than thirty degrees Celsius.

So in comparing 5w40 motor oil and 10w40 motor oil, the 10w40 motor oil is thicker. However, there aren’t many differences in their fuel economy of 5w40 motor oil and 10w40 motor oil.

Hot Weather

The 5w40 motor oil has its differences from the 10w40 motor oil. The first numerical number of the motor oil will indicate the minimum temperature for which your vehicle is made. The letter w means winter.

The 10w40 motor oil has a number ten. The letter w also means winter. The 5w40 motor oil is thinner if you compare it to the 10w40 motor oil in low temperatures; however, if the temperature is higher, both 5w40 motor oil and 10w40 motor oil will perform similarly with the same viscosity.

Can I Use 5w40 Instead of 10w40?

The best choice is to use the motor oil and to pick the viscosity that your manufacturer recommends. So if your vehicle recommends 10w40 motor oil, then use 10w40 motor oil; if your manufacturer recommends 5w40 motor oil, then use the 5w40 motor oil. But with this, the viscosity of your motor oil might also need to be changed depending on the extreme conditions that your vehicle is in.

You might have to use a different viscosity if you are driving in cold weather or hot weather. Sometimes, your manufacturer will also give you a range of the oil viscosities in certain conditions. You can also refer to your owner’s manual.

The 10w40 motor oil is suitable for ambient temperatures, and this is what most of us encounter. But to answer the question, you can use a 5w40 motor instead of a 10w40 motor oil. However, the rule of thumb is to use what is recommended.

Accidentally Used 5w40 Instead of 10w40: Is It Ok?

Yes, it is okay. There will be no significant damages or serious problems that you will be encountering. Some car drivers have stated that you can cause 5w40 motor oil if the 10w40 motor oil is recommended.

In operating temperatures, both of the motor oil is 40wt, and they are alike. However, both 5w40 motor oil and 10w40 motor oil are thicker than 40wt in operating temperatures in cold temperatures.

The 5w40 motor oil is also more synthetic. On the other hand, a 10w40 motor oil is petroleum-based.

5w40 vs 10w40 High Mileage

Mechanics are using 5w40 motor oil to support high mileage engines. This is because it is thicker under hear than any other motor oil. It also lubricated moving parts even better. On the other hand, 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.

Which Is Better, 5w40 or 10w40 Oil?

This depends on your vehicle, the temperature, and a lot of other factors. One of the motor oil is thinner than the other. The 5w40 motor oil is thinner in comparison to the 10w40 motor oil in low temperatures.

If the temperature is high, then both of the motor oils will perform a similar function. So one motor oil cannot be the best for every vehicle.

Each engine is different, and the engine manufacturer will be recommending different motor oil for each of their engines. So the best way to do this is to refer to your owner’s manual and find out the recommended motor oil for your engine.

When Should I Use 5w40 And When 10w40?

Knowing what to use in between 5w40 motor oil and 10w40 motor oil will depend on the winter temperature of your area. The 5w40 motor oil is much better in starting your engine in low temperatures. It will also flow more efficiently in a specific environment.

If you are driving in high temperatures, you must use 10w40 motor oil. The 10w40 motor oil can operate at a working temperature up to one hundred four degrees Fahrenheit. The 10w40 motor oil is also much preferable if you will put heavy loads on your engine.

This can apply to commercial vehicles. The thickness of the 10w40 motor oil is much better in dealing with an increased load. It can also decrease any metal-to-metal contact.

5w40 vs. 10w40 Toyota

The recommended oil for all Toyota engines is 5w30 motor oil. The mention of 5w40 motor oil and 10w40 motor oil are not in the recommended motor oil for Toyota engines.