5w40 vs 15w40 Motor Oil

5w40 vs 15w40 Motor Oil

A car is a combination of hundreds of complex vehicles. When the engine starts, the combination of these machines keeps the car in motion. Therefore, maintaining these parts and machines is essential to maintaining the health of any vehicle.

There are many tools and components to achieve this purpose of maintaining a car. Lubricating oil is one of the materials used to maintain auto parts. Transmission oil is used as a lubricant for vehicle maintenance tools. Here we will compare those too and find the best one for you.

5w40 Vs 15w40 Table

Brand Valvoline & Viscosity 5w-40

Brand Shell & Viscosity 15w-40

Full Synthetic Motor Oil

Synthetic Blend Engine Oil

Extra Wear Protection Designed To Keep Engine Parts Like New

Provides Triple Protection Plus Technology Protects Against Wear

This Oil Is Suitable To Use In Winter.

This Oil Can Be Used In Winter As Well As In Summer.

Extra Detergents Fight Sludge And Deposits

Exceptional Deposit Control/Cleanliness

Quickly Start And Provide Quick Protection In Cold Weather

Better Oil Flow In Low Temperature & Shear Stability

Increased Thermal And Oxidation Stability

High Thermal And Oxidation Stability

The Design Temperature Of 5w40 Engine Oil Does Not Exceed 5 Degrees

The lowest temperature provided by 15w40 engine oil is 15 degrees

What Is Motor Oil?

Motor oil or engine oil is one of several substances composed of base oil. The base oil is rich in various additives, especially anti-wear additives, detergents, dispersants, and multi-grade oils, it also includes a viscosity index improver.

Besides, motor oils lubricate internal combustion engines. The main function of engine oil is to reduce friction and wear on moving parts and to clean engine sludge. And the oxidation of the lubricant improves the sealing of the piston ring. It cools the engine by absorbing the heat of the moving parts.

5w40 Short Review

5w40 is one kind of motor oil. The 5w40 engine oil has its own name, which is associated with the custom type to achieve the goals required by the engine. The name is mainly implemented in conjunction with the specification to initiate the planned engine lubrication process.

5w means that the oil must have a certain maximum viscosity or fluidity under low-temperature conditions in winter. Five means the oil viscosity is zero degrees, w means winter, and 40 means oil viscosity is 100 degrees.

According to its duties, the engine oil that uses this oil is not too watery. But they must also be viscous enough to allow them to flow through the motor without problems. This oil can only be used in winter. Now let’s check out the Specification we find in our observation.


  • Active detergent
  • Excellent thermal and oxidation stability.
  • Low fuel consumption.
  • Reduced deposits.
  • The accumulation of sludge can ensure a long and clean engine life.
  • Resist oil aging and provide long-term protection during the oil change.
  • Quickly start and provide quick protection in cold weather.
  • Extend the service life of the engine.
  • High viscosity index.
  • Excellent overall lubrication and wear protection, suitable for all riding styles, and the conditions range from easy to difficult.
  • Outstanding thermal and oxidative stability.

15w40 Short Review

15w40 engine oil is another engine oil used to run the engine in the motor system. 15w40 oil is also used to indicate the perspective view. Engine oil 15w40 indicates that it is a multi-grade oil based on mineral oil.

Names with different letters and numbers define different aspects of the oil type. In this case, 15 means the lowest temperature is 15 degrees Celsius, and 40 means the viscosity is centistokes. This means that the oil is stable both in winter and summer so that it can be used throughout the year.

The oil is equipped with an additive package to ensure high engine performance. The viscosity index of the oil means that the oil has the same viscosity as SAE 15Woil at low temperatures. Both diesel and gasoline engines use multi-grade oil 15W40. Let’s get the specification that we find.


  • High thermal and oxidation stability.
  • Shear stability.
  • Advanced dispersancy
  • Reduce sludge formation and deposition and increase the viscosity.
  • Control deposits and neutralize the acid.
  • Wear protection and viscosity control.
  • Cleaner engines and longer component life.
  • Used oil pumpability
  • Excellent low-temperature properties.

Our Observation

While choosing, you should first consider the most suitable products recommended by the manufacturer for the car. This is very important because it often determines the car’s warranty and ensures that the engine is in good condition.

It is important to note that climate plays a significant role in choosing the best oil options. For example, in colder areas, 5w40 is much better than 15w40 because it allows a faster and quieter cold start.

However, for those who do not live in a very cold area, the 15W viscosity is much better. In this case, the stability provided by 15 W under high-temperature conditions is much more effective. Therefore, when choosing between 5W40 and 15 W40 for one whole year, 15W would be a potential one at ambient temperatures.

Can you mix both 5w40 and 15w40 and use them?

Yes, you can mix these two types of oils if you want. There will not be any significant change in the automobile’s motor system. That means no positive or negative effects if you mix those oils. So it is completely your wish to do so.

Frequently Asked Questions (FAQ)

There is no definitive answer to this question as it depends on a number of factors. However, in general, 5w40 oil is better for high-performance engines and 15w40 oil is better for engines that work hard under extreme conditions. Ultimately, it is best to consult your engine’s owner manual or a professional mechanic to determine which oil is best for your specific engine.

Yes, it is perfectly fine to use 5w40 oil instead of 15w40. In fact, 5w40 oil is often recommended for use in high-performance engines.

15w40 oil is a bit thicker than 5w40 oil, so it may provide better protection in very cold or very hot weather conditions. However, if you live in an area with moderate weather conditions, 5w40 oil will likely work just as well (if not better) than 15w40 oil.

There are a few different factors to consider when deciding whether or not to use 15W-40 oil in your vehicle. Temperature is one of the biggest considerations – in general, thicker oils like 15W-40 are better for warmer climates, while thinner oils are better for cooler climates. If you live in an area with very cold winters, you may want to switch to a thinner oil for the winter months. Other factors to consider include the type of engine in your vehicle and your driving habits. Talk to your mechanic or refer to your owner’s manual for specific recommendations.
Yes, 15w40 oil is good for petrol engines. This oil provides excellent protection for engine components and helps to prolong engine life. This oil is also suitable for use in high-performance engines.



The main difference between 5w40 and 15w40 is that the oil is much thinner at low temperatures, so it does not require a long time to reach the engine. On the other hand, 15w40 has much more viscosity.

This oil can handle heat up to high-temperature conditions because it has good resistance to oxidation and thermal stability. It was shown that 5W40 is suitable for people who live in cold areas, while 15W40 is suitable for people who live in hot areas.


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