The Key Differences Between a 5W-30 and 0W-30 Engine Oil


In our previous articles, we have emphasised just how important an engine oil is for your car. It performs several functions such as protecting moving parts, acting as a seal and even cooling the engine. Using the right or wrong oil for your car can be the difference between an efficient, long-life engine or one that is potentially facing catastrophic failure.

So, while we know that choosing the right oil for your vehicle is essential, it can be quite confusing when you see a range of products, grades and quantities on the shelf. In this post, we are looking at the 0W-30 and 5W-30 engine oil grades, products that are prominent for today’s vehicles but have some key differences which mean they may or may not be suitable for your vehicle.


What is a 0W-30 Engine Oil?Quartz Ineo First 0W-30 Engine Oil

0W-30 grades are a very high performing, synthetic grade engine oil. As engine technology advances, the grades used in these engines have changed, with the 0W-30 grade being one of the most important. The most important identifying feature of the 0W-30 is that it is a. The 0W-30 is a fully synthetic engine oil type that uses several types of additives that are capable of enhancing and improving engine performance, increasing fuel economy as the level of friction is reduced. Other essential properties to increase fuel economy include thermal stability, low-temperature start-up and thermal protection.

Depending on the recommendations from your owner’s manual, the 0W-30 can be used instead of other grades. Again, this will be dictated by the Original Equipment Manufacturer (OEM) as they built the engine with very precise specifications.


What is a 5W-30 Engine OilIneo ECS 5W-30 Engine Oil

5W-30 engine oils are the most common on the market, but as brand-new vehicle makes and models come online, the engine technologies change making these products obsolete. The first thing to notice is that the 5W-30 engine oil is a higher viscosity oil than the 0W-30. 5w-30 engine oil’s capacity to operate within a wide variety of engine types and under a wide range of temperature conditions makes it incredibly versatile.

Whether you have a petrol or diesel engine, 5w-30 is quite often the recommended engine oil because it flows more easily in winter temperatures. Simultaneously, it’s able to maintain a safe viscosity when the engine is operating in the summer heat, when an oil with lower viscosity is susceptible to breaking down, causing greater wear on engine parts. Therefore, the all-round performance and protection abilities in varying climate conditions mean that 5W-30 oils are popular among users today.


What do the numbers mean on the Packaging?Engine Oil Viscosity

Today’s engine oils are multigrade which in this case is highlighted by the 5W or 0W-30. Introduced by the Society of Automotive Engineers (SAE), these numbers indicate the engine oil’s viscosity and help establish which oil grade is best suited for a particular temperature range.

The numbers on a multigrade oil are given based on the rate at which they flow at different temperatures (their viscosity). Viscosity is the single most important requirement of engine oil and is defined as the opposition or resistance to flow.  For example, water would have a lower viscosity than a liquid such as syrup. The lower the grade or number, the thinner it is and the lower its viscosity will be.

The “W” found with the first number of an oil grade stands for Winter.  The lower the number, the lower the viscosity of the oil and better suited it is to winter temperatures. At relatively low temperatures, once the engine is started and begins to heat up, the oil will flow faster than other grades and protect the moving parts faster than a 5 or 10W for example. The packaging of the oil will highlight the temperatures that the oil will begin to flow at.


What is Operating Temperature?

The inside of a car

All lubricants, no matter their function have a temperature range in which they can operate efficiently. As the temperature increases the oil thins, while at lower temperatures the oil stays thick. Each of these ranges can adversely affect the performance level of your oil. Another factor to take into account is the velocity that the engine is creating. As the speed increases, temperature also increases, while the slower the velocity, the lower the temperature again affecting the performance and protection level of the oil. A 0W-30 grade can operate at much lower temperatures than a 5W-30 as the oil will flow faster thereby protecting the engine at an earlier stage. Some engines are not suited for a 0W-30, always check your owner’s manual before adding oil to your engine.

Choosing the Right Engine Oil for your Car

Can These Engine Oil Grades Help me Save on Fuel?

One of the biggest topics in the market is how engine oils can save on fuel. Especially prominent in the supply chain and agricultural sectors, fuel savings can be made by using a lower viscosity grade in your car. 0W-30 engine oil is well-known for its ability to improve fuel economy. The 0W-30 engine oil is a lower viscosity than a 5W-30 meaning it is thinner. As the 0W-30 is a lower viscosity, its resistance to flow is lower. The lower viscosity grade flows through the engine faster and helps the parts perform their roles more efficiently as they reduce friction. The engine requires less fuel to perform its essential operations, reducing usage and your costs.

Choosing the Right Oil for My CarWhich Oil Logo

Now that we understand the key differences between these 2 grades, the next step is to find out if they are suitable for your vehicle. Factors such as age, mileage, current condition, and the most important, what the manufacturer recommends.  The engine manufacturer has put in countless hours into designing the engine with the suitability of the oil crucial to ensure optimal performance. Your owners will always indicate to you what oil your vehicle needs and the regular oil change intervals.

To also help with your search Finol always recommends using the Which Oil lubricant advisor to ensure you’re using the correct oils every time. The lubricant advisor, available for use at offers many features to give you a fast and reliable recommendation. Just type in the registration of your car or van and you will get your results instantaneously. For further help talk to our technical team at 01-455 5484 or go to

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Published on: March 29, 2022

Filled Under: Technical Articles

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