5W30 Vs. 5W40: How Are They Different From Each Other?

The demand for synthetic oils is a game-changer in the motor vehicle industry.

These oils have been around for close to fifteen years, and even though they cost more than other products, they are popular since they are consistent and perform exceptionally. 

The most common is 5W30 and 5W40, which differ in terms of specification, properties, and performance.

Here we have a comprehensive analysis and comparison of the two oil brands. Between 5W30 vs. 5W40, which is the best? Keep reading.

5W30 vs. 5W40: An Overview

5W30 vs 5W40

If you have a lawnmower or pressure washer, you’d want engine oil that will work best under any temperature conditions.

Unfortunately, most people are usually at crossroads when choosing the right engine oil. Engine oils help protect your machine by minimizing friction, accelerating the wear and tear of the engine’s movable parts.

There is a plethora of engine oils on the market, and the 5w30 and 5w40 are the most popular. 

For both 5w40 and 5w30, the w represents winter provided by the Society of Automotive Engineers or SAE multi grading system.

The number appearing before the w is the oil’s viscosity or the thickness of the oil at lower temperatures.

On the other hand, the number after the w means the oil’s viscosity at high temperature when the engine is running. As you can see, the difference comes in the number after the w.

This implies that the oil’s viscosity resists the flow, and if it’s very thick, there will be some resistance.

On the contrary, very thin oil fails to protect the engine’s moving parts from probable wear and tear.  

Difference Between 5W40 And 5W30 Explained

difference between 5W40 and 5W30

To help you decide on the best engine oil for your machinery, we’ll look at viscosity and the performance of each oil type under different weather conditions.

Here are the differences.

  1. Viscosity

Viscosity is the flow of oil through your engine. For example, 5w30 has a viscosity of between 9.3 to 12.5 mm2/s, while 5w40 has a viscosity of between 12.5 to 16.3 mm2/s.

Therefore, it means that 5w40 has a higher working viscosity than 5w30. Typically a lubricant with less viscosity is more fluid, has more liquid, and therefore flows easily.

On the other hand, a larger viscosity means the engine oil will be thicker and flow slowly. At low temperatures, thin oils can pour well into thick oils.

Thick oils can form a protective film at high temperatures and maintain film strength and pressure.

On the same note, 5w30 has a kinematic viscosity of 2.9mPas, whereas 5w40 oil is 3.5mPas. Typically, each motor oil is viscous at low temperature, and the situation remains the same even at -30°C.

However, when comparing the two, 5w40 is more efficient at high temperatures. Indeed it works best even at 50°C than it would at 30°C.

It means that both motor oils have a winter viscosity rating of 5 and are effective even at -30°C.

In addition, they have more viscosity at a lower temperature when you compare with other oil brands such as 10w40.

Therefore, 5w40 motor oil can be used in powerful engines that can operate in high temperatures and with higher loads.

If your machine is low performance or you don’t drive often, you can consider 5w30 oils. For instance, if you’re using the lawnmower to cut grass in your backyard, 5w30 oils would be a great choice. 

Additionally, 5w30 motor oils are suitable for certain engine parts like the oil pumps since they are clean and long-lasting despite reducing the temperature range.

 When choosing the best motor oil for your engine, it’s essential to consider both protection and efficiency or performance.

For example, higher viscous oil while the engine is running protects the moving parts; however, it can be very thick and may not efficiently safeguard its performance.

In addition, engines vary in construction, and using the wrong oil will give you problems. Likewise, it’s crucial to consult your engine manufacturer for advice on the best grade of oil.

  1. Fuel Efficiency

When you compare the fuel efficiency between the two engine oils, 5w30 works with a wide variety of machines compared to 5w40.

Therefore, it’s more efficient and economical. When it comes to cost, 5w30 costs more than 5w40; however, it’s a valuable purchase. 

  1. Temperature Settings

As you can see, the main difference between 5W40 vs. 5W30 is the viscosity in hot weather. So whereas 5w30 is a good option for cold weather, 5w40 is best to use in hot weather.

When it comes to grading, 5w30 has a 30 rating, whereas 5w40 has a 40 rating, and therefore it has a higher viscosity in high temperature.

This means that 5w40 has better performance on the engine and general working of the engine.

30-grade oil performs well with a temperature variance of -25° C and 25° C. Likewise; the 40-grade engine oil is suitable for a temperature variance of between 25° C to 35°C.

  1. High-Shear Rate Viscosity

The 40-grade motor oil has a high shear viscosity rating of 3.5 at 150g, whereas the 30-grade motor oil has a shear viscosity of 2.9 at 150g.

Subsequently, this means that the oil with a high shear rate can withstand a heavy load. For fluidity, the 30-grade oil is more fluid but offers less pressure when compared to 40-grade oil.

  1. Mileage

Changing the engine oil is essential as it keeps the engine working efficiently. In addition, it helps in lubricating the parts regardless of the mileage.

When choosing between 5w30 and 5w40, you can think about the mileage of the mileage. A machine’s mileage is considered high or low depending on its age.

Machinery with low mileage has low oil demand, and therefore, this means the engine parts can enjoy a longer life.

On the other hand, if the machine has lower mileage, there’s low usage, and therefore 5w30 oil will work best under this situation.

On the other hand, a machine with high mileage will have higher oil demands, and therefore you can choose 5w40 oil. 

Also Read: Difference Between10W30 and SAE 30.

Choosing The Right Motor Oil

5W40 vs. 5W30

Your machinery’s engine needs the right oil for it to function properly. Poor quality oil can affect its performance and reduce its lifespan.

Motor oil lubricates the movable components of the engine and prevents them from rubbing on each other, which can lead to wear and tear.

Using the wrong motor oil can also speed up wear and tear. It’s vital to change the engine oil regularly and remove the dirty oil.

Usually, contaminated oil does not cool the engine, nor does it offer the right lubrication. Choosing the right motor oil reduces the maintenance of your engine, which is both time and cost-saving.

We shall look at the features of both engine oil and give our verdict.

Other than cars, machineries such as lawnmowers or pressure washers use synthetic oils at different temperature ranges.

A Short Review of 5w30 Engine Oil

5w30 is engine oil that makes the machine sound like it’s new. It offers the best lubrication as well as protection for the engine.

It helps improve the efficiency of your engine and protects against wear. 5w30 is a versatile oil, and you can use it in different conditions. It’s ideal for gasoline, multi-valve, and diesel engines.

If you are interested to learn more about it, read the difference between 5W30 and 10W30.

A Short Review of 5w40 Engine Oil

5w40 engine oil is crude based and suitable for gasoline as well as diesel engines. It’s popular with machinery under warranty, especially those that use leaded or unleaded gasoline.

It has low volatility and has excellent thinning resistance to heat. It has many approvals and helps in minimizing oil utilization.

What To Keep In Mind When Choosing The Right Engine

Given the difference between 5W40 and 5W30, there are several things to keep in mind.

  • Viscosity

Viscosity is the first thing to consider when shopping for your engine oil. It’s the ease of fluid flow at a given temperature.

Typically, thick engine oil is more viscous than thin oil. In our review, 5w30 and 5w40 have viscosity represented by the number 5, whereas w stands for winter.

Both oils have the same viscosity of 5 in winter conditions, and therefore it’s relatively low.

Thus, this means that the motor oil will flow even at lower temperatures; because of this, it can flow smoothly on the engine, and therefore, it’s high quality compared to other brands such as 10w or 20w.

In our review, both oils have suitable viscosity, which is well distributed in the motor regardless of the weather condition.

The best thing about this scenario is that it helps reduce any damage to the engine. It also minimizes the resistance of the movable parts as the engine is running.

  • Weather

The weather is yet another essential consideration when shopping for the best engine oil for your machinery. If you live in a cold-weather location, you’ll need a motor oil that has a low viscosity.

Such oil will flow easily through the system and performs exceptionally well. However, if you live in hot weather situations, you’ll need a motor oil that has high viscosity.

On the same note, it should strike a good balance not to affect its fluidity. Too much viscosity makes the engine too thin, which won’t lubricate the movable parts easily.

Thus it can affect the lifespan of your engine and increases the costs.

  • Price

Different types of engine oils come at different prices. From our review, it’s evident that 5w30 is more expensive than 5w40. However, 5w40 performs better in strenuous situations.

If your machine has lower mileage, it means that its oil demands are lower. Therefore, 5w30 engine oil is a good value.

Nonetheless, it would be best to consider other factors such as viscosity and weather when choosing the engine oil.

On the flip side, 5w40 is cheaper than 5w40, and therefore you can select it if you use your machine frequently. It works best under extreme conditions, yet it’s a good value for money since it’s cheaper.

Quick Summary

  • Whether or climate plays a vital role in choosing the right engine oil for your machine. A lower temperature means lower viscosity.
  • As motor oil flows through the system, it ensures the engine runs efficiently. Therefore 5w30 and 5w40 oils are famous for cooler temperatures than other models.
  • High temperatures mean there’s higher viscosity. However, this doesn’t affect the flow of the oil.
  • Too much thin oil will not lubricate the engine at high temperatures, leading to increased wear and tear. Likewise, thicker oil will not work well in cold temperatures.
  • When choosing, consider whether 5w30 or 5w40 is too thin or thick.

5w30 Versus 5w40: Which Is Better?

Without a doubt, 5w30 motor oil is the most common on the market and can be used in different engines. Also, it’s suitable for different weather conditions.

Because of its versatility, it’s famous among vehicle users, especially during winter periods. It’s also popular in hot weather.

Even though 5w40 is not as famous as 5w30, it’s durable and helps boost your engine’s health. It protects your engine from the accumulation of sludge and, therefore, helpful in extending its lifespan.

It means that the engine oil moves well through the components and makes the engine perform even at freezing temperatures.

During hot weather, it’s favorable even in hot weather since it’s thick and protects your engine.

Overall, in deciding between 5w30 vs. 5w40, viscosity is the main factor to consider and each oil’s performance in varying temperatures.


There’s no telling which oil is better for your lawnmower or pressure washer’s engine as it depends on your circumstances from the discussion.

It’s vital to read the manual guide before choosing the right oil for you.

Typically, the manufacture suggests the best oil to use depending on your engine type. Also, it’s crucial to pick the right oil that will not affect its warranty or cause it to wear and tear fast.

5w30 is more popular because it’s readily available and has wide use. However, 5w40 performs exceptionally well in hot temperatures and is cheaper than 5w30 oil.

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1 thought on “5W30 Vs. 5W40: How Are They Different From Each Other?”

  1. In my experience; 5w40 is more expensive than 5w30. This is basically because 5w40 is a “newer” fully synthetic oil whereas 5w30 “was” semisynthetic, although the Castrol magnatec 5w30 C3 (which I use in my BMW 325i 2008) states fully synthetic on the bottles. Your cars manual will state the oil specification(s) to use in your engine so all you need to do is make sure that information appears on the oil bottle label. My manual states the oil should meet BMW LL01/04, so that’s what I look for.
    Through experience, I’ve also found that 5w30 lasts longer and requires very few top ups due to consumption vs 5w40. I like in UK.
    It might also be an idea to proof read your text too as there are confusing statements such as “ On the flip side, 5w40 is cheaper than 5w40”.
    Hope this helps.

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