What’s the Difference Between 5W-30 vs 5W-40 Oil?

In the automotive world, the difference between 5W-30 and 5W-40 engine oil types often leaves car owners confused and trapped in a dilemma when choosing the ideal motor oil for their vehicle. With both grades offering distinct benefits, it’s essential to explore their properties and specifications to find the best one for your car. 

5W-30 is a common grade, known for its versatility across a wide range of temperatures. Making it a preferred choice for those looking to balance performance and fuel efficiency. Meanwhile, 5W-40 offers a thicker protection layer, ideal for higher temperatures and engines that endure more wear. Safeguarding movable parts against friction and wear. 

The main purpose of both oils is to protect your engine. But picking the right one necessitates precision and an understanding of your car’s needs. This guide serves to help clear the air, providing advice and a compared perspective on these engine oil types . Ensuring that your selection process is not just a shot in the dark but an informed decision aimed at enhancing your vehicle’s performance and longevity.

What do the Letters and Numbers Mean on Engine Oil?

Before diving into the differences between 5W-30 and 5W-40. It’s worth recapping what the letters and numbers on engine oil bottles represent. The ‘W’ stands for Winter, indicating the oil’s protection level at low temperatures. Ensuring your engine starts and runs smoothly even on the coldest mornings. The number before the ‘W’ shows the viscosity level at colder temperatures, which hints at how well it flows.

 Post-‘W’, the second number reveals the oil’s viscosity, or thickness at high operation temperatures. Engine oils are graded based on this viscosity level and their winter temperature protection level. The main thing to remember is, the higher the oil viscosity number. The thicker and more viscous it is at warmer temperatures. This prime information about oil grades is essential when choosing the right type for your vehicle, as explained in any comprehensive engine oil guide.

Embarking on a personal journey of understanding the variances between 5W-30 and 5W-40 oils for my car. I discovered that 5W-30 is generally preferred for its versatility in a wide range of operating temperatures, offering a balanced equation in terms of performance and fuel efficiency. 

On the other hand, 5W-40 tends to be a go-to for vehicles that face more demanding conditions or higher ambient temperatures, given its thicker consistency. Which provides an additional layer of protection. Both engine oil grades excel in safeguarding the engine’s movable parts against friction and wear. Yet the selection hinges on aligning with your vehicle’s specific needs and manufacturer’s recommendations. This exploration underlies the importance of not merely choosing engine oil. But making an educated decision that contributes to the longevity and efficiency of one’s car.

What is 5W-30 Engine Oil?

When faced with the decision of selecting engine oil . The difference between 5W-30 and 5W-40 can leave many car enthusiasts confused. Both oils maintain a cold temperature rating of -25°C, ensuring that engines remain protected against the chill. Preserving normal viscosity levels and avoiding cold start issues. 

5W-30 is tailored for drivers residing in regions experiencing a mix of cold and warmer temperatures. Providing an ideal balance of warm-temperature protection and performance efficiency. It’s akin to choosing a versatile outfit that adapts seamlessly from a cool morning to a warm afternoon. On the other hand, 5W-40 steps up in viscosity level, offering enhanced protection in warmer climates. Much like a stronger sunscreen that safeguards where lighter options might fall short. 

Despite their shared cold temperature rating, the primary difference lies in their performance across temperature variations, with the numerical divergence indicating each oil’s specific protective capabilities in fluctuating weather conditions.

What Is The Difference Between 5w30 and 5w40

In the world of car maintenance, understanding the differences between engine oil types. Notably 5W-30 and 5W-40, is essential for any driver aiming to optimize their vehicle’s performance. Both oils are prevalent in the automotive industry, serving as common types of auto parts designed to safeguard the engine under diverse conditions. 5W-30 is often advised for lighter engine loads and colder climates. Offering a smoother start-up in low temperatures due to its thinner viscosity. 

Conversely, 5W-40, with its thicker consistency, is ideal for cars facing heavier loads or operating in warmer environments. This knowledge empowers drivers to decide on the best oil for their car, considering the key differences in viscosity can significantly impact engine health and efficiency. Whether you’re performing a routine oil change or seeking the most suitable type for your vehicle. Blending personal experience with expert advice ensures your car benefits from the right engine oil, underlining the importance of informed car maintenance in the automotive industry.


Viscosity is essentially how we define a liquid’s resistance to flow. In the realm of engine oils, it’s not just a spec—it’s the heart of your car’s working viscosity. For instance, 5w30, with a viscosity range of 9.3 to 12.5mm2/s, is adept at thinly coating engine parts. Facilitating a smoother flow under lower temperatures. On the flip side, 5w40 steps in with an operating viscosity of 12.5 to 16.3mm2/s. Offering a larger viscosity that bolsters film strength at higher temperatures, making it better suited for demanding engine is affected by oil deposits.

Fuel Economy

When it comes to fuel efficiency, 5w30 is often highlighted as more fuel economical than 5w40 due to its thinner consistency, which reduces internal drag within engine kinds. This translates to less effort for your engine to churn, leading to slightly better fuel economy. Whether you’re scouting the Cheapest Place to buy Motor Oil or debating between the Best Brands of Car Motor Oils. Remembering the microscopic economy scales between these oils can guide you towards making sound decisions for both your vehicle and wallet.

Temperature Range

Exploring the temperature range of these motor oils unveils that 5w40 heralds a broader scope. Performing reliably between -25OC to 35OC. Alternatively, 5w30 is engineered for a slightly narrower spectrum, optimizing its efficiency in environments where extreme cold isn’t much of an issue. Drawing from personal maintenance tips shared by seasoned car experts. The choice between these oils often boils down to matching your oil’s temperature range with your geographical climate and vehicle’s performance demands.

By leaning on both personal experience and a trove of knowledge collected over years. I’ve learned that understanding the nuances of 5w30 and 5w40 goes beyond merely picking an oil; it’s about tailoring your car’s lifeline to its unique environment and operational needs.

Should I Use Fully Synthetic Engine Oil?

  • Gold Standard of Engine Oil: Opting for fully synthetic oil elevates your vehicle’s performance, offering outstanding protection and long-lasting lubrication.
  • Investment and Environment: While it demands a higher cost, fully synthetic oil is more environmentally friendly, reducing waste compared to non-synthetic or part-synthetic oils.
  • Improved Efficiency: The refined composition of fully synthetic oil ensures better performance through enhanced engine efficiency. Characterized by lower emissions and reduced engine wear.
  • Outstanding Protection: Provides robust protection to internal engine components against wear and corrosion, significantly extending engine life.
  • Redox Oil Finder: Utilizing tools like the Redox Oil Finder makes it quick and easy to find the right engine oil for your car by entering your car’s reg number. Ensuring access to a full range of premium engine oils tailored to your vehicle.

5w30 vs 5w40 – Which One is Better?

In the dynamic world of car maintenance, choosing between 5W-30 and 5W-40 engine oils hinges on understanding their differences. 5W-30 is advised for lighter engine loads and colder climates, providing better start-up lubrication, while 5W-40 is ideal for heavier loads and warmer environments, offering thicker protection. This knowledge enables drivers to make informed decisions, ensuring optimal car health and performance.

Highlighting Features of 5w30

When diving into the nuanced world of motor oil, 5w30 stands out as a versatile guardian for your vehicle engine. My journey started with a switch to 5w30, notably the Amsoil 5w30 LS Synthetic European Motor Oil. For its unmatched ability to protect and maintain engine parts in their best condition. 

The advantage of this oil lies in its lubricating ability that gracefully allows every movable part of the engine to operate smoothly, slashing reducing friction and wear significantly. The high-grade additives and formula utilized in its making not only save fuel but clean effectively, marking a notable increase in fuel economy. This synthesis of features dramatically improves the overall performance of the vehicle engine. Making it feel akin to a new one. 

Its excellent wear protection is a beacon of reliability for those used to normal to extreme driving conditions. Rendering it suitable for both diesel and gasoline engines, including multi-valve fuel engines.

Highlighting Features of 5w40

Shifting gears to 5w40, a crude-based motor oil known for its resilience, it becomes the preferred choice for drivers prioritizing thinning resistance against heat. Suitable for both diesel and gasoline engines, including cars that run on either unleaded or leaded gasoline. Its lesser volatility helps to reduce oil utilization. This property not only guarantees a longer life for the car but also secures. The warranty of newer vehicles by ensuring consistent performance under varying temperatures. 

The 5w40 oil has earned multiple approvals from users for its adeptness at keeping the engine running like a well-oiled machine. Its robustness protecting against the harsh realities of both wear and tear. It presents a substantial variety in the market. With enough types of oils being available that cater to a large spectrum of people looking for specific features to suit their cars.

In my exploration of motor oils, I found that choosing between 5w30 and 5w40 isn’t just about selecting an oil; it’s about deciding the best way to protect and enhance your car. Ensuring its movable parts are shielded against wear through reducing friction, irrespective of the conditions. The market offers a variety of options, but understanding these oils’ features and how they translate into performance can influence your preferred choice among the types of oils available.


In conclusion, the choice between 5W-30 and 5W-40 engine oils is more than a matter of numbers—it’s about understanding the specific needs of your vehicle and the conditions under which it operates. 5W-30 oil, with its lower viscosity, tends to be better suited for colder climates and provides a balance between fuel efficiency and protection. 

On the other hand, 5W-40 oil, with its thicker consistency, offers enhanced protection for engines operating under the stress of higher temperatures or heavier loads. Making an informed decision between these two oils requires considering the manufacturer’s recommendations, your driving habits, and the prevalent environmental conditions. 

Armed with the right knowledge, car owners can ensure their engine’s longevity and optimal performance by selecting the oil that best meets their vehicle’s demands.


What happens if I use 5w40 instead of 5W-30?

Originally Answered: What happens if I use 5w40 instead of 5w30? Nothing much, maybe a bit less gas mileage. Usually oils that are 40 weight and higher are for diesel engines. These oils contain more detergents and other additives to counteract the soot and other byproducts of combustion specific to diesels.

Which is better, 5w30 or 5w40 oil?

If you use your vehicle in urban conditions, often sit in traffic jams, drive at high speeds, and your car is old, buy oil with the 5w40 viscosity. But if you prefer calm driving, and fuel economy and eco-friendliness are important for you – choose a product with 5w30 marking.

What is 5W 40 oil used for?

The 5W-40 viscosity is a prevalent recommendation for performance engines in European vehicles with gas-powered engines, and in American diesel pickup trucks. We offer 5W-40 oils for gasoline- and diesel-powered engines. If you have a modern European vehicle, consider Mobil 1™ Formula M or Mobil Super™ Synthetic Euro.

Is 5w40 better in older engines?

On the other hand, 5W40 fully synthetic engine oil is suitable for engines having higher performance or slightly older engines that used to run on 5W30.

Is 5w40 better than 5w30 for high mileage?

Switching from 5w30 to 5w-40 is ok. But the general idea is: if you feel your engine shaking and noisy with that thin oil 5w30. Then try to use thick oil 5w-40 to damp the engine. You will feel the engine run smoother for the engine with high miles.

Is 5w40 good for summer?

5w40 is better for starting your engine at low temperatures as it flows more easily at these temperatures. When the engine is running and hot, 5w40 and 10w40 have high viscosity and are equally effective in protecting against engine wear.