When you buy a motor vehicle, motor oil is the second most important fluid for the vehicle after fuel. Choosing the right grade of oil is crucial. Unless you know how 0w40 or 10w40 impacts the performance, you can’t do that.
So, what is 0w40 vs 10w40? Both of these are multigrade motor oils. The main difference between them is in their viscosity at low temperatures. 0w40 is more suitable in cold-temperature areas because it is less viscous at low temperatures. At high temperatures, both oils have similar viscosity. Learn all the similarities and differences between these two motor oils to understand where you can use them.
Learn all the similarities and differences between these two motor oils to understand where you can use them.
0w40 vs 10w40: Comparison Chart
The following chart will give you a quick idea of the similarities and differences between these two oil grades.
| Features | 0w40 | 10w40 |
| Low-Temperature Range | -40°F or -40°C | -13°F or -25°C |
| High-Temperature Range | 212°F or 100°C | 212°F or 100°C |
| Low Temperature Efficiency | Higher | Lower |
| High-Temperature Efficiency | Lower | Higher |
| Oil Consumption | Higher | Lower |
| Kinematic Viscosity (at 40°C) | 71 sq.mm/s | 88.7 sq.mm/s |
| Flashpoint | 226°C | 230°C |
| Fuel Consumption | Lower | Higher |
| Price | $27.97 | $22.67 |
What Does 0w40 Mean?
Before understanding how different motor oils impact engine performance and fuel efficiency, you need to know about the oil grades. I will talk about viscosity first to give you a clear idea.
If you want to move your palm through water, it will be relatively easy. But when you do the same with honey, you feel a lot of resistance. It is because the honey is more viscous than water. In other words, the resistance to motion a fluid shows is its viscosity.
So, what are the numbers in an oil grade, actually? The numbers in a motor oil grade express the viscosity. Some grades have two numbers, for example, 0 and 40. And the numbers have a letter between them, which is ‘w’.
Here, 0 denotes the viscosity rating of the oil at low temperatures. When the temperature is extremely low during winter, this oil will behave as a less viscous well. So it will be thin enough to flow through the engine. As a result, the engine can perform efficiently.
But when the temperature exceeds 100°C, the same oil will be much thicker. Its viscosity rating will be similar to a 40-weight oil at high temperatures. So the oil won’t be thinned out too much at higher temperatures.
What Does 10w40 Mean?
It will be easier to explain this grade now as you already know about viscosity. Here, 10 indicates that this oil has a higher viscosity at low temperatures. So, the oil will be thicker than 0w40 during a cold start. But once the engine is running at its optimal temperature, this oil will have the same viscosity as the 0w40. In real-life scenarios, the viscosity of these oils can vary slightly depending on operating temperatures, engine types, fuel types, etc.
0w40 vs 10w40: Detailed Comparison
Let’s take a closer look at the properties of these oils in different conditions.
Low Temperature Viscosity
0w40 has a lower viscosity rating at low temperatures. When the temperature is extremely low during winter, this oil will be thinner. So it will flow faster. During a cold start, this oil grade can help your engine perform optimally with a faster flow. This oil stays thin at temperatures up to -40°C.
10w40 is thicker than 0w40 at low temperatures. So, it won’t perform efficiently during cold starts. The oil will flow slower than 0w40, so the engine might overheat. This oil is only suitable for cold temperatures up to -25°C.
High-Temperature Viscosity
When the engine has reached its operating temperature, both oils will perform the same. They will be thicker than low-temperature conditions, which prevents the breakdown of the oil. This is why both oils are multigrade oils, which means the same oil has two different grades at two temperatures.
Both oils can withstand high temperatures up to 40°C. At that temperature, the viscosity of these oils will be the same as a 40-weight oil.
Engine Performance
Thinner oils are more suitable for low-performance or lighter engines. For example, 0w40 is a thinner oil than 10w40, so it is commonly used in passenger cars. Due to the lower viscosity at low temperatures, it can withstand less engine loads.
On the other hand, more viscous oils are necessary for heavy engines. For example, heavy diesel engines with DPF or high-performance gasoline engines will benefit from oils like 10w40. This oil can withstand higher loads while not being too thick or viscous.
Engine Oil Consumption
Engine consumes thinner oils more than thicker oils. For example, 0w40 will be consumed at a higher rate than the 10w40. This is because thinner or less viscous oils are more prone to breaking down and causing sludge.
10w40 is a more cost-friendly option because it has a lower consumption rate than 0w40.
Fuel Consumption
Even though thinner oils have a higher oil consumption rate, they will result in more fuel-efficient engines. As they flow through the engine easily, the engine quickly reaches the operating temperature. So, the engine becomes more fuel efficient with 0w40.
But 10w40 is a thicker oil, so the engine efficiency is lower before reaching the operating temperature. As a result, this oil will cause a lower fuel efficiency.
Price
0w40 retails at $27.97, while 10w40 has a retail price of $22.67. So, 0w40 is more expensive than 10w40.
0w40 vs 10w40: Which One Should You Choose?
It depends on multiple factors, such as your climate, engine type, fuel type, and more.
The general rule is to use 0w40 if you live in a cold climate region. In such areas, a thinner oil will benefit the engine more. Also, 0w40 is better if you have a light engine.
10w40 is slightly better for warm weather. If you live in an area with decent weather all year round, you can use 10w40 without any issues. Above all, you should stick to the oil grade suggested by the manufacturer to ensure maximum engine performance and durability.
FAQs
You might be looking for answers to these questions as well. Check them out.
Q: Can I use 10w40 instead of 0w40?
If you drive the car in warm climates, you can use 10w40 instead of 0w40. For colder climates, you should only use 0w40 because it flows better at low temperatures.
Q: Can I mix 0w40 with 10w40?
I don’t recommend mixing engine oils of different grades. Use only one grade of engine oil that suits your driving conditions and engine specifications.
Final Thoughts
Engine oil grades often seem confusing, especially to new car owners. Multigrade oils like 0w40 or 10w40 have marginal differences, so the confusion here is higher. I provided an in-depth comparison of 0w40 vs 10w40 to show you their similarities and differences. You must understand the impact of viscosity on engine performance, oil consumption, fuel efficiency, and engine durability. It will help you get the best performance and a longer service life from the engine. Always choose the right grade of engine oil for your vehicle to prevent sludge, faster oil breakdowns, and other issues.