10w-40 or 5w-30: What’s the Best Choice? Unravel the Facts

Car mechanic open car hood repairs system checking oil motor level for refill and clean in car garage service.

The selection of motor oil is critical for the optimal performance, functionality, and durability of the engine. Ideally, it is not recommended to swap 10w-40 or 5w-30 oils, but only after the keen observance of their behavior and properties. The viscosity of any oil is its most fundamental character that further enhances or diminishes its effects. Manufacturer recommendations are significant factors that can help if the swapping is authorized or not destructive for the engine. Before finalizing the swap, go through the potential benefits and the risks of the exchange. Ultimately, the selection will be based on many factors, including the needs and the requirements, along with the practical implications.

How Are 5w-30 and 10w-40 Oil Different?

Different grade oils exhibit different characteristics that basically arises because of difference in the viscosities. But before heading directly towards the difference, one should know what the oils are individually and what their particular properties are.

What is 5w-30?

5W-30 Engine Oil

The 5w-30 oil exhibits a good range of viscosities at different temperatures, making it a versatile oil pick. As the name suggests, the 5 before W shows the viscosity at lower temperatures. It is categorized as 5, which is very low viscosity and adequate flow at lower temperatures. On the contrary, the oil is graded as 30 ranked viscous fuel at operating temperature. This highly viscous fuel will provide optimal engine protection. 

What is 10w-40?

10w-40 Engine Oil

The 10w-40 oil is slightly more viscous and hence thicker. It exhibits higher viscosity at both cold temperature and operating temperature. At cold temperatures, it measures the viscosity range of 10, and with increasing operating temperature, the viscosity also expands up to 40 ranked fuel.

Difference between the Two

The major difference is that their viscosities affect the applications, benefits, and risks. The most vital distinction upon which we can differentiate the two is the sound start of 5w-30 at colder temperatures, while the enhanced engine protection of 10w-40 at higher temperatures. 

How Does Viscosity Impact the Performance?

Viscosity is the measure of resistance a fluid experiences while flowing. The greater the viscosity, the greater will be the resistance in the flow, and the fuel is thicker. In contrast, lower viscosity offers low resistance in the flow, and the fuel is thinner and runny. Viscosity impacts the performance of several parameters that directly affect the performance of the engine. Fuel efficiency, lubrication, the vitality of the engine, and the performance of the vehicle are all dependent on the viscosity of the fuel being used. Thermal stability and wear protection are also the characteristics that are defined by the viscosity. The overall impact is influenced by the type of vehicle, climate, and the design of the engine, whether the viscous fuel will be more suitable or the thinner one.

Benefits of Using 10w-40

  • In warm weather areas, 10w-40 provides better lubricant and consistency as it offers higher viscosity as compared to 5w-30 at higher temperatures. Also, there are two factors that generate heat: the outside temperature and the heat dissipation inside the system because of the engine. It depicts the need to have an optimal viscous fluid that maintains the required fluid flow rate and lubrication consistently, and 10w-40 is highly beneficial in such a scenario.
  • Engine wear protection is a focused factor for many vehicle owners as engines are the brains of vehicles and are very costly if disturbed. In order to keep the wear and tear protection sound enough, the use of viscous fluid that can cast a better oil coating on several components while functioning is definitely a need.
  • There are cases when the thicker oil reduces the oil consumption by reducing the risk of fuel leakage. Moreover, the 10w-40 is more viscous than the 5w-30, which clearly displays that it will not get thinner and have consistent lubrication even at higher temperatures.

Risks and Drawbacks of Using 10w-40

  • In extreme weather areas, where there are harsh winters, 10w-40 offers more viscosity as compared to 5w-30, which may cause hindrance in the smooth and easy start of the engine.
  • Generic trends show that thinner oil boosts fuel efficiency while thicker fuels may cause more fuel. If fuel efficiency is essential, go as per the manufacturer’s recommendation.
  • With increased technology, the new engines are prone to work more efficiently with thinner fuels, increasing fuel efficiency and reducing emissions. 

Considerations for Using 10w-40 and 5w-30

Choosing between 10w-40 or 5w-30 can significantly impact engine functionality. Always refer to the vehicle’s manual for the manufacturer’s recommendation of oil viscosity to get optimal engine performance and longevity.

Engine Efficiency

The type of engine matters the most when choosing between 10w-40 and 5w-30 motor oils. Older or High-mileage engines with a wide tolerance benefit from 10w-40. In order to protect engine parts, it provides thicker oil film to maintain the functionality. Oils with thicker viscosity can lead to reduced fuel economy compared to thinner oils. Conversely, in modern engines, a thin oil with lower tolerance levels like 5w-30 performs optimally for easy flow and better lubrication properties.

Engine Wear and Tear Prevention

For engines with high levels of wear and tear, 10w-40 provides better wear protection. 5w30 is suitable for cold starts because it has low viscosity. During startup, its quick lubrication helps in reducing initial wear.

Climatic Concerns

In cold weather conditions, 5w-30 is a better option due to its better flow at low temperatures. It provides quick and adequate lubrication to protect the components of the engine during cold starts. If you face fluctuations in temperature, 5w-30 is a good option, providing protection against cold start and high-temperature performance. In hot weather conditions, 10w-40 works significantly. It maintains the lubrication properties and viscosity at high temperatures.

Implications of using 10w-40 instead of 5w-30

Using 10w-40 has certain implications when used instead of 5w-30. Out of which, some of the most influential implications are as follows: 

  • The manufacturer doesn’t recommend it. Utilizing 10w-40 in such scenarios may cause voidance of warranty.
  • The thicker fuels can have strong frictional effects inside the engine, causing the efficiency of the engine to be reduced. Not only will fuel efficiency be influenced, but also the components inside the engine may suffer.
  • Viscous fuel like 10w-40 instead of 5w-30 definitely causes more emissions and is not an environment-friendly approach.

These implications are not undeniable, but they act according to the given circumstances. Depending on the temperature and vehicle type, there can be scenarios that will eventually define the most suitable oil.

Manufacturer Recommendations and Expert Advice

Above all, the manufacturer’s recommendations and expert advice play a crucial role in deciding the most suitable oil. Many internal factors, including the type of materials used, the engine’s design, and the fuel lines’ capability to carry the fuel, eventually enhance or diminish the performance. If you are looking to have a safe swap from 5w-30 to 10w-40, you are highly recommended to check the manufacturer’s manual and go as per the suggestions. In order to optimize the vehicle’s performance at maximum, these two are vital along with countryside constraints.

  • 5w-20 Vs 5w-30: Head to Head Comparison – Understand the intricacies of engine oil viscosity to select the perfect one for your vehicle – Click here.
  • 5w-30 Vs 10w-30: Detailed Comparison – Dive deeper into the world of motor oils and see which viscosity stands tall – Click here.
  • 0w-20 Vs 5w-20: Detailed Comparison – Discover how temperature ranges influence the performance of your engine oil – Click here.
  • SAE 30 Vs 5w-30: Underline The Difference – Decipher the specifics of single-grade and multi-grade oils for optimal engine protection – Click here.
  • SAE 30 Vs 10w-30: Head-To-Head Comparison – Understand the world of engine oils better by comparing two popular choices – Click here.

Related Posts

Understanding ILSAC GF-6: The Best Engine Oils for Modern Vehicles

Understanding ILSAC GF-6: The Best Engine Oils for Modern Vehicles

Jobelle Corpuz8 min read

ILSAC GF-6, crafted by the International Lubricant Standardization and Approval Committee (ILSAC), sets benchmarks for engine oil performance. It’s tailored…

Reducing Oil Consumption for Catalytic Converter Efficiency

Reducing Oil Consumption for Catalytic Converter Efficiency

Jobelle Corpuz8 min read

Ever wonder how your car helps protect the environment? Enter the catalytic converter: a key component in modern vehicles’ exhaust…

best oil for nissan 350z

Best Oil For Nissan 350Z

Ryan McCain7 min read

Do you know which is the best oil for your Nissan 350Z? Choosing the best oil for your VQ35HR engine…