5W30 vs 5W40 Motor Oil

5W30 vs 5W40 Motor Oil

Do you trust your technician when it comes to changing your car’s engine oil? We recommend completing your homework because no one knows your automobile better than you. There’s no need to travel too far in your search; this article will save you a lot of time.

Knowing what is ideal for your car’s performance will save you a lot of money on maintenance and significantly increase its performance.

Is it a 5W30 or a 5W40 motor oil? Which is the better option for your car? We recommend that you learn about the importance of choosing the correct engine oil before deciding which one is best.

Similarities with 5W30 and 5W40

To begin, consider the similarities between the two engine oils.

  • Both are efficient in cold temperatures and so lubricate the engine effectively in these conditions.
  • Because both engine oils flow freely throughout the engine’s components and allow the engine to function at a high level.
  • Both of these oils are suitable for usage in hotter climates since their thickness is sufficient to give enough lubrication and protection to the engine.

Consider two products: 5W-30 and 5W-40 viscosity motor oils. What is the difference between them? 

The marking is done in line with the SAE (Society of Automotive Engineers) worldwide standard for assessing the viscosity of engine lubricants. Oils are primarily used to lubricate the moving components of an automobile engine. Numbers represent the viscosity of fuels and lubricants at low and high temperatures. 

The engine should be run in low-temperature mode using an oil that has a low viscosity. On the other hand, high temperatures need the use of a composition that can maintain a lubricating thin layer between the components.

Highlights of 5W30 and 5W40

5W40 Oil

  • 5W40 is a motor oil that keeps the engine running smoothly and prevents friction from overheating the moving components. 
  • 5W40 helps to keep the engine clean by burning by-products and protects it from oxidation by transferring heat from the combustion cycle. The motor oil’s performance is influenced by the exterior and internal temperatures of the operating engine. 
  • The viscosity of 5W40 motor oil in the winter is 5, implying it is less viscous at very low temperatures. The highest viscosity rating is 40, which indicates that it is only viscous when heated to a high temperature. 
  • This engine oil is mostly used by Europeans with gas engines and by American diesel pickup trucks.
  • The 5W40 motor oil is a crude-based motor oil that works well in both diesel and gasoline engines. This type of motor oil is typically used in vehicles that are still under warranty. Here are some key characteristics of this oil category:
  • Suitable for vehicles that use unleaded and leaded gasoline
  • Low volatility
  • Helps to reduce oil utilization
  • Excellent thinning resistance against heat

5W30 Oil

  • Engine oil with a viscosity of 5W30 has a reduced viscosity. The W in 5W30 stands for “WINTER,” while the number refers to the oil’s viscosity at high temperatures.
  • The Society of Automotive Engineers (SAE) developed a numerical code system for classifying engine oil. The oil is graded according to its viscosity characteristic. Although the viscosity of oil fluctuates with temperature, multi-graded oil protects the temperature range.
  • The number 5 in 5W30 refers to the oil’s viscosity at low temperatures. If the number is lower, the oil will be thinner, allowing it to flow more freely through the engine even at low temperatures. At typical operating temperatures, the number 30 reflects how fine the oil is functioning.
  • 5W30 is also known as multi-graded oil since it is thin enough to flow at low temperatures and fine enough to flow in high temperatures, regardless of the temperature.
  • 5W30 is a type of motor oil that makes your car’s engine sound like it’s brand new. It gives your car’s engine more lubrication and protection.
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Furthermore, it aids in improving the vehicle’s fuel efficiency. The following are some of the most notable characteristics of this motor oil:

  1. Improves overall performance
  2. Offers excellent wear protection
  3. Lubricates the engine
  4. Used for normal to extreme driving conditions
  5. Suitable for diesel, gasoline, and multi-valve fuel engines

The Difference Between 5W30 and 5W40

Difference Between 5W30 and 5W40


Many individuals prefer 5W30 to 5W40 when deciding between the two. This is due to the fact that 5W30 motor oil has a smoother impact on the oil pump and a better flow through the engine when the engine is hot. 

Both of these motor oils, on the other hand, perform well for delivering quicker lubrication to engine components when the automobile is started.


The range of temperatures in the oils differs between the 5W30 and 5W40 oils, and it increases the oils’ performance in the engine. When exposed to low temperatures, the best engine oil should not condense, and when exposed to hot temperatures, it should not evaporate.

5W30 vs 5W40

5W40 has a lower temperature of -250 degrees Celsius and a higher temperature of 350 degrees Celsius, whereas 5W30 has a lower temperature of -250 degrees Celsius and a higher temperature of 350 degrees Celsius, indicating that the oils have a comparable temperature range.

In reality, this implies that each oil is equally viscous at lower temperatures and will stay viscous at -30°C. In comparison, 5W40 oil outperforms 5W30 oils at higher temperatures, being effective up to 50°C instead of 30°C.

Winter viscosity ratings of five apply to 5W40 and 5W30 motor oils, indicating that they are effective down to -30°C and are more viscous at extremely low temperatures than, for instance, 10w40 oils.

As a result, 5W40 oils are more likely to be used in higher-performance engines with greater operating temperatures and loads than the usual – such as those driving in urban areas, in traffic, or at particularly high speeds.

5W30 oils are an excellent choice if your vehicle is not meant to be operated at high speeds or if you travel at a slower, more eco-friendly pace. These are better for specific engine components like oil pumps, can clean the engine better, and have longer lifespans owing to their lower temperature range.

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Cold test for 5W30 and 5W40: 

Price Comparison

The price of 5W30 is higher than that of 5W40.

Engine oil in the 5W30 range is expensive, but engine oil in the 5W40 range is not. 5W30 is not readily accessible anywhere, but 5W40 is widely available. In comparison to 5W30, 5W40 has a greater viscosity rate.

Because of the variations in performance, the oils have different pricing. According to current prices acquired from an online Engine Oil supplier TYRES.NET, the cost of 5W30 oil ranges from ₤11.49 to ₤11.84, while the price of 5W40 oil ranges from ₤11.99 to ₤15.36, indicating that the price of 5W40 oil is greater than 5W30 oil. However, even though the change is minor, it results in a cent saved.

Fuel Economy

5W30 is thinner and easier to flow at high temperatures. It causes less resistance between the moving components inside your car’s engine, resulting in slightly better fuel efficiency because the engine does not have to work as hard to move these parts while driving. The thicker 5W40 is the polar opposite.

Because the oils operate differently, there are variances in the fuel efficiency as well. When comparing the fuel efficiency of 5W30 with 5W40, 5W30 is more cost-effective than 5W40 because of its viscosity, which allows it to function with a wider range of engines. 

5W30 is often rated the best in terms of performance based on fuel efficiency.

As research was done by SAE(Society Of Automotive Engineers), the effect of using low viscosity engine oil can improve fuel efficiency.


The viscosity of engine oil refers to how easily it pours at a specific temperature. The viscosity of engine oil will increase as it becomes thicker, 5W30 vs. 5W40, and vice versa. 

A number represents the viscosity of the engine oil. The number 5 is followed by the letter W in 5W30 and 5W40, representing “Winter.” Because other engine oils, such as 20w, are too viscous to flow at low temperatures, it is considered excellent grade engine oil. 

5W30 vs 5W40

The viscosity of both of these engine oils enables uniform distribution throughout the motor, even when it is cold. As a result, it reduces the amount of damage and resistance caused by the engine’s components.

  • Low-Shear-Rate Viscosity 

At 100g, the working viscosity of 40 ranges from 12.5 to 16.3 mm2/s. At 100g, the operating viscosity of 30 ranges from 9.3 to 12.5 mm2/s. When cold, both oils are 5 grade. However, at operational temperatures, 5W30 is 30 grade, and 5W40 is 40 grade. 

With greater temperatures in the summer, 5W40 has a higher viscosity than 5W30, which helps to keep the engine running smoothly.

  • High-Shear Rate Viscosity

This value is min 3.5 at 150g for a working viscosity of 40. This value should be at least 2.9 at 150g for a working viscosity of 30. This indication, to a large part, indicates how much oil can withstand severe stresses.

Viscosity difference 5W30 vs 5W40: 

When To Use 5W40

The viscosity of 5W-40 is commonly recommended for performance engines in European gas-powered cars and American diesel pickup trucks. For gasoline and diesel engines, we provide 5W-40 oils.

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When To Use 5W30 

Light-duty diesel engines, light-duty gasoline engines, and automobile gasoline engines all utilize 5W30. Engine oil with a viscosity of 5W30 is recommended for engines operating in cold regions since it allows for better flow at lower temperatures.

The difference between 5W30 and 5W40 is significant. They are both motor oils, but their viscosity differs, and they function differently in different situations. 

It will be simple to determine which engine oil is superior. The engine of your car determines the motor oil’s performance.

Since the major distinction between 5W30 and 5W40 is their viscosity, their characteristics are also distinct.

Because 5W30 is high-priced engine oil, it performs well in the engine’s internal parts, ensuring that the car operates smoothly. This engine oil will also help you in the future.

According to the comparison, 5W30 is superior to 5W40.


Q: Can I mix 5W30 and 5W40 oil?

A: Yes, you may combine the two oils because they have the same low-temperature viscosity rating of (5) and will flow equally to the top ends. Mixing various oils will not harm your engine, but it will not enhance performance.

Q: Can I use 10W 40 instead of 5W40?

A: It’s typically better to use the oil viscosity recommended by the manufacturer. If they say to utilize 10–40, then do so.

If you are driving in harsh circumstances, though, the oil’s viscosity you use must alter. If you regularly drive in very cold (below freezing and below 0F) or very hot circumstances, you would require a different oil viscosity.

Q; Will 5W30 hurt a 5W40 engine?

A: No, it will not hurt your engine. It will depend on the temperature range. 5W30 and 5W40 oils are mainly used for winter or cold temperatures; still, they have thinner quality for the hot temperatures, like 5W30 can be used from -30° to 30° temperature range and 5W40 can be used from -40° to 40° capacity.

Q: What happens if I use 5W40 instead of 5W30?

A: Because the guidelines are so similar, there won’t be much of a functional difference between a 5W30 and a 5W40. Under light load operating conditions, a smaller weight may be more efficient, while a larger weight may provide better protection under higher load operating conditions.

Q: Is 5W40 better for high mileage cars?

A: A heavy-grade 5W40 oil, according to Mobil Oil’s website, is recommended for use in cars with a diesel engine with high mileage. The use of heavy-duty 5W40 oils extends the life of diesel engines by protecting them from leaks.

There are “significant variances” between these and conventional oils, according to Z. George Zhang, Ph.D., director of Valvoline Technical International.

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