5w30 vs 5w40 | Complete Difference With Facts

Whether you get your motor oil from the garage or incline toward doing it yourself – It is essential to get the right motor oil for your vehicle’s engine.

Motor oil greases up the vehicle’s engine to keep it working without a hitch. It covers the parts and safeguards them from wear and tear while the motor is running.

5w30 and 5w40 are the most well-known grades of motor oil. Engine manufacturers all over the world suggest them.

The grade values are appointed by the Society of Automotive Engineers (SAE). The different grades show the thickness of the oil at various temperatures.

5w30 vs 5w40

Viscosity of Oils

The Viscosity or Consistency is the thickness of a fluid. A thick fluid has good resistance against the flow.

If the oil is excessively thick, it won’t flow through the engine. If it is too runny, it can not protect engine parts as they heat up while running.

The viscosity of the oil increases as the temperature goes down.  When the temperature increases, the oil begins to thin down. The oil that is too thin will not be able to protect engine components.


What do 5w30 and 5w40 mean?

In the SAE evaluating framework, ‘w’ stands for winter.

The number before w states the oil’s capacity to flow at low temperatures (0 degrees F). The lower the number, the better the oil moves through the engine during winters.

The number after w shows the oil’s resistance to thinning at high temperatures (100 degrees F). A larger number shows a higher weight of the oil – this means that it is more resistant to thinning. 

5w30 and 5w40 are both formulated to keep engines running smoothly in winter climates. The two oils have a similar winter viscosity, 5, implying that both are great for starting engines at low temperatures.

Following is a table to look at the critical properties of 5w30 and 5w40 engine oils.

Motor Oil Properties5w305w40
Suitable enginesLight-duty petrol, diesel and gasoline enginesHigh-performance diesel and gasoline engines
ThicknessViscous at low temperature, becomes runny as the temperature risesViscous at both high and low temperatures
Fuel efficiencyBetter fuel efficiency, runs economicallyBurns out faster
Exposure to high temperaturesCan work well at high temperatures but starts to break down Remains viscous at high temperature
Engine performanceFlows smoothly as it is lighter, easier to pump through the engineSlightly heavy, has high oil pressure, offers better protection for engine parts
Suitable climateSuitable for cold climatesSuitable for warmer climates
Value for moneyMore expensive, lasts longerLess expensive, delivers performance but burns quickly

Similarities between 5w30 and 5w40

While looking at the properties of 5w30 and 5w40, it is easy to see why both motor oils are popular choices. The two oils behave similarly at low temperatures. This changes when the engine reaches working temperatures, and the oils give different results. 

Following is a rundown of similarities and differences between  5w30 and 5w40.


  • Suitable during winter climates

5w30 and 5w40 oils have very similar low-temperature properties. Both of them are formulated to ensure that engines work flawlessly during cold start. They likewise protect parts from friction and keep up with the temperature while the vehicle runs.

Both the oils are viscous at – 30 degrees C and fluid at – 35 degrees C. They can easily flow through the engine and protect it in chilly winter months.


  • Viscosity during cold start 

5w30 and 5w40 have similar thicknesses during cold start.

They are easy to pour and are circulated well by the oil pump. This guarantees good protection for engine parts with smooth and even coating. 


Differences between 5w30 and 5w40

5w30 and 5w40 have some key differences in how they perform during usage. This becomes clearer when the vehicle reaches working temperatures.


  • Reaction to high temperature

5w30 and 5w40 have comparable consistency at lower temperatures up to – 30 degrees C. However, this changes as the temperature go up.

5w30 keeps the engine running smoothly up to 30 degrees C, after which it begins to break down. Meanwhile, 5w40 keeps its consistency up to 50 degrees C. It continues to perform well even after the engine warms up considerably. 5w40 is also good for warmer climates.


  • Engine Performance

5w30 is the lighter engine oil and flows easily through the oil pump. It takes less power from the engine and cools parts rapidly. This keeps the engine working smoothly for long durations.

Use 5w30 in your vehicle if you prefer fuel efficiency and drive-through consistent traffic. 

5w40 is viscous at higher temperatures and is heavier while pumping through the engine. This leads to a higher working temperature and puts strain on the battery. This effect is irrelevant, as 5w40 delivers good performance in high-temperature conditions. 

Use 5w40 in sports cars and urban vehicles that need to speed up and dial back quickly.

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5w30 vs 10w30 | Crucial Differences + Imp. FAQs

  • Fuel efficiency

5w30 offers better efficiency. Although it has a smaller temperature range, it is lighter and is easily pumped throughout the engine. It lasts longer under consistent temperature conditions and your engine needs fewer refills. 

5w40 gives better performance and has a wider temperature range. It can keep the engine running despite rapid temperature changes. As a result, it finishes sooner and needs to be topped off more frequently. 


  • Value for money

5w30 is the more expensive oil. It is a popular choice among drivers and suits a wide variety of vehicles. Using 5w30 means you need less frequent refills, and it offers great value for money.

5w40 is more reasonable and is readily available even when 5w30 isn’t. It draws more power from the engine and burns out quicker. Nonetheless, it is great for high-performance motors and can pull heavy loads.


Choosing the right oil for your engine 

While comparing 5w30 and 5w40, picking one option can be difficult as the two oils are very popular. The two oils have similar physical properties and give great benefits in performance. Picking the right oil is also critical to draw out your engine’s lifespan.

The following pointers will be helpful while choosing the best oil for your engine’s needs.

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  • Follow the manufacturer’s recommendation

The main thing to remember is to follow the manufacturer’s recommendation. Your vehicle’s engine is built and intended to work best under specific conditions. These are met by the engine oil, which greases up and coats the parts to keep them working without wear.

Engine makers recommend the most suitable oil to use so that your engine gives the best performance. Follow these instructions to make sure that your vehicle gives good mileage and has a long lifespan.


  • Consider usage conditions

Another thing to consider is the type of vehicle you own and the conditions of its use.

In urban conditions, vehicles sit in traffic for extended periods of time and speed up on clear roads. In this case, the engine oil needs to keep up with the motor’s high-performance needs. It also needs to function well in both low and high temperatures. If this is you, using 5w40 oil is your smartest choice.

Whereas, vehicles that aren’t intended for superior execution can do well with 5w30. It offers great mileage, fuel efficiency and gives value for money. Using 5w30 in your vehicle guarantees that your engine stays in optimum condition for a long time.


Should I use 5w30 in a 5w40 engine?

It is common for drivers and mechanics to use one oil instead of the other. This can happen when the engine is running short, or the favored motor oil is unavailable.

While 5w30 and 5w40 have similar-sounding names and thicknesses, they act differently when the motor is running.

You can use 5w30 oil rather than 5w40 as long as the oil pump creates sufficient pressure. This helps to make the oil flow in all important areas of the engine. Using 5w30 in a 5w40 engine also helps, as 5w30 is lighter and flows more easily. Many drivers take advantage of this to keep their engines running cooler.

The two oils have similar viscosities at low temperatures, but 5w30 will begin to thin down as the engine gets hotter. This can happen when you drive at a fast speed for long durations. If the engine reaches very high temperatures, the oil film covering the parts will break. Without this film, the engine can sustain damage from grating between the uncoated metal parts. A similar issue occurs during the summer months, or in high-performance conditions. 

In conclusion, the best engine oil for your needs is the one suggested by the engine manufacturers. 

Use 5w30 to top off your engine only when 5w40 is unavailable. In such cases, stick to the ideal climate and usage conditions while using the lighter oil.



5w30 and 5w40 are two popular grades of engine oil. They are great for winter climates and have similar consistencies at – 30 degrees C. The two oils do a good job of greasing up the engine parts without a hitch and protecting them from wear. 

While they are similar at low temperatures, their performance changes when the engine heats up. 5w30 and 5w40 act differently at working temperatures. This results in several differences in your engine’s performance. 

5w30 is the lighter oil. It flows easily through the engine and stays viscous up to a temperature of 30 degrees C. This is great for driving at moderate speeds. 5w30 additionally gives better fuel economy, greater mileage and keeps the engine in good shape for a long time. It lasts longer than 5w40 and offers good value for money. 

If you drive light-duty petrol or diesel car, go at moderate speed,s and want good fuel economy, then 5w30 is the ideal motor oil for you.  

5w40 is heavier than 5w30 and remains viscous at higher temperatures (50 degrees C). It additionally has high oil pressure and moves easily through the oil pump. 5w40 is best for high-performance engines. It works well at high speeds, while lifting heavy loads, and running in hotter climates.

If you drive a high-performance urban vehicle and have to stop and go frequently in traffic, then 5w40 is your choice of motor oil. 

While picking engine oils, it is best to go with the manufacturer’s recommendation. This guarantees that your vehicle runs smoothly over the long haul.