As winter is nearby, you may want to know which engine oil will be a better choice. While you look for one, you’ll come across two popular engine oil choices for cold weather: 5W10 and 10W40.
So, what is the difference between 5W10 and 10W40? Generally, both of these oils offer good engine performance and better fuel economy. However, the oil’s viscosity and thickness of 5W40 is lower and thinner than 10W40.
Well, there’s more to this comparison. And we’ll share the similarities, too. Keep reading to find out the best choice for your car.
A Quick Comparison Between 5W40 VS 10W40 Engine Oil
Take a quick look at the table of comparison between 5W40 vs 10W40 oil before we dive into the elaborate discussion:
| Features | 5W40 | 10W40 |
| Definition | Lightweight engine oil with low viscosity that allows it to run smoothly | Thicker and offer high viscosity that may not run as smoothly as 5W40 |
| Viscosity Level | 5 and 40 | 10 and 40 |
| Suitable temperatures | -30° to 32°C | -5° to 50°C |
| Fuel Economy | Improves fuel economy and engine performance | Less influence on fuel economy and engine performance |
| Engine Abrasion | It may increase wear and abrasion | Prevents wear and abrasion |
| Friction Intensity | Offers less friction | Creates moderate friction |
| Suitability | Passenger vehicle engines | High-performance engines |
| Lifespan | 6,000-8,000 miles | 8,000-10,000 miles |
What Does These Numbers Mean in 5W40 and 10W40 Oil?
The numbers on the motor oil container indicate the viscosity grade of the oil. Viscosity determines an oil’s thickness and ability to flow at different temperatures.
For cold startups, the first number is the oil viscosity measurement. ‘5’ or ’10’ shows how thin the oil is and its flow rate through engine components at colder temperatures.
The ‘W’ in the number stands for ‘Winter’, highlighting the oil’s ability to maintain viscosity in cold conditions. Oils with this designation are also referred to as multi-grade oils.
Regarding the ’40’ on the oil label, it signifies the viscosity index or the oil’s thickness at regular operating temperatures. A higher number means the oil’s viscosity remains more consistent across temperature changes.
This provides more consistent lubrication regardless of the engine temperature. So, in short —
- The number ‘5’ or ‘10′ refers to the thinness of the oil in the cold temperature (such as 0° F).
- The “W” indicates the cold temperature of winter.
The last number, ‘40,’ refers to the oil’s thickness at normal temperature (such as 212° F).
Key Differences Between 5W40 VS 10W40 Engine Oil
Now, let’s discover the key differences between these two engine oils in detail:
1. Viscosity Level
The main distinction between 5W40 and 10W40 engine oils is their viscosity grades. As we mentioned, the first number indicates the viscosity level of the oils.
As the 5W40 engine oil has less viscosity(5 to 40), it can run through the components more freely and spread evenly than 10W40 (10 to 40).
2. Suitable Application for Weather
However, 10W40 is more versatile than 5W40. Freezing temperature and winter weather conditions are mostly ideal for the 5W40. Still, you can use it for warm weather conditions like 32° Celsius.
In contrast, the 10W40 can be applied both in cold, warm, and very hot temperatures. However, it’s advisable not to use it in freezing weather as thick oil may take longer time to spread.
Thus, 10W40 engine oil is ideal for use in -5° to 50° weather temperature.
3. Oil Thickness
5W40 engine oil is designed for use in regular passenger vehicles, whereas 10W40 is made for use in high-performance vehicles.
Additionally, 10W40 has a higher viscosity level. That’s why 10W40 is designed with a thicker oil concentration than 5W40.
4. Friction Intensity
Regarding friction levels, 5W40 oil creates less resistance between moving engine components than 10W40. Its thinner viscosity grade of 5 allows smoother flow and transition between parts.
Less friction improves performance as less energy is lost to overcoming viscosity. However, the thinner film may not protect against engine wear and abrasion in the long term.
5. Higher Heat Protection
Because 10W40 has a slightly higher cold viscosity of 10, it maintains lubricating qualities better than 5W40 at higher operating temperatures. The film is more resistant to breakdown.
6. Fuel Economy
The thinner the oil is, the better fuel economy is. When the engine operates more smoothly with it, it uses less fuel to produce the same power.
As a thinner oil, 5W40 faces less drag within the motor than 10W40. This makes 5W40 an ideal choice for drivers seeking to maximize their vehicle’s fuel efficiency through lubricant.
7. Lifespan
5W40 oil should be replaced approximately every 6,000-7,000 miles due to its shorter service life of 8,000 miles. In contrast, 10W40 lasts longer before needing replacement. You can drive about 8,000-9,000 miles before changing oil due to its higher 10,000-mile service life. In general, 5W40 requires more frequent changes than 10W40 due to its thinner formulation.
Are There Any Similarities Between 5W40 and 10W40 Engine Oil?
Yes, despite the differences, there are some key similarities between 5W40 and 10W40 engine oils. Such as:
1. Maintenance of Viscosity Grades
Both are multi-grade oils that maintain viscosity at high and low temperatures. This allows them to provide adequate lubrication in varying weather conditions.
2. Similar Specifications
5W40 and 10W40 meet the same specifications and engineering approvals from major automotive organizations like API, ILSAC, and OEMs. This indicates comparable base oil and additive technology.
3. Properties
The lubrication properties of each oil help protect engine components from wear. They form protective films that shield metal surfaces as they withstand combustion byproducts.
4. Price
Regarding price, 5W40 and 10W40 cost around the same amount per liter/quart at most auto parts stores, around $20 – $40. Their widespread acceptance keeps prices competitive.
Which One is Better: 5W40 and 10W40?
5W40 oil is a good all-around oil used. It’s less viscous at cold temperatures than 10W40 oil, so it’s easier to start your engine in cold weather.
On the other hand, the 10W40 oil is more viscous at cold temperatures than the 5W40 oil. So, it may be more challenging to start your engine in cold temperatures.
However, it’s a good choice for warmer and cold climates. It’s more viscous at high temperatures than 5W40 oil, which provides better protection for your engine’s components in hot weather.
FAQs
Here are some commonly asked questions regarding 5W40 and 10W40 oil:
Q: Can I use 5W40 and 10W40 engine oil alternatively in freezing weather?
Yes, you can. But we recommend using 5W40 engine oil in freezing weather. It’s because this oil spreads evenly through the engine and starts the engine more efficiently than 10W40.
Q: Can I mix 5W40 with 10W40?
It’s not recommended to mix different viscosity engine oils like 5W40 with 10W40 in the same engine, as it can disrupt the lubricating properties. Stick to one weight of oil.
Conclusion
Now, you know the differences when comparing 5W40 vs 10W40, along with the meaning of numbers, similarities, and which is better. You can use both of these oils in cold temperatures for better engine performance and to support high mileage.
When you pick one of these oils, remember that both of these oils are mostly suitable for cold and hot temperatures. But for freezing weather, 5W40 is the ideal choice. The rest depends on your preference. So, which one did you want to pick?