Multi-grade engine oils are becoming more popular thanks to their operating capabilities in a wide range of temperatures. Among the various motor oil grades available, two commonly used options are 10W30 and 5W30.
While the 5W30 oil is thinner and flows more easily at cold temperatures, the 10W30 oil is thicker and performs better in high-temperature conditions. The 5W30 is more pricey, fuel-efficient, and suits passenger cars. With its high viscosity, the cost-effective 10W30 is more suitable for older, high-mileage engines. In our 10W30 vs 5W30 motor oil comparison guide, we’ll explore what these grades mean and which one you should choose. Let’s dive in!
10W30 and 5W30: What Do the Numbers Imply?
Before we jump into the comparison, let’s learn what these grades mean for engine oils. The U.S. Society of Automotive Engineers has designated a number or code (between 5 and 50) for engine oils to specify their viscosity.
So, all these numbers in 10W30 and 5W30 oil viscosity ratings indicate the oil’s thickness or resistance to flow at different temperatures.
- First Number: The ‘W’ in the SAE oil code means ‘Winter’, and the first number before the ‘W’ refers to the oil’s viscosity at cold temperatures. If the first number is higher, the oil will be thicker. For example, the first number of the 5W30 is lower than the 10W30. So, 5W30 oils have a lower viscosity in cold temperature conditions.
- Second Number: As for the second number, it indicates the oil’s viscosity at operating temperatures (100°C). The higher the second number, the thicker the oil will be at high temperatures. As both 5W30 and 10W30 share the same second number, they have the same viscosity in extremely hot engine conditions.
5W30 Vs. 10W30: Which Motor Oil Is Better?
Now, it’s time to compare the two oil grades and select the better one for your vehicle type. We’ll consider the effectiveness of these oils at different temperatures and judge their overall performance. Here’s a quick overview:
| Comparable Features | 5W30 | 10W30 | Winner |
| Effectiveness in Cold Temperatures | More effective due to its low viscosity | Less effective as it flows slower | 5W30 |
| Effectiveness in High Temperatures | Less Effective with its thin oil film | Offers better protection against wear and tear | 10W30 |
| Operating Temperature Range | Broader range from -42°C to 30°C | Lower range from -18°C to 30°C | 5W30 |
| Suitability for Engine and Vehicle Types | Used for modern engines and lightweight passenger cars | More suitable for older engines and heavy commercial vehicles | Both |
| Fuel Efficiency | Saves more fuel due to its lower viscosity | Slightly less fuel-efficient | 5W30 |
Effectiveness in Cold Temperatures
If you live in a particularly cold area and you need to cold-start your engine regularly, the 5W30 is a better choice. As the first number in the 5W30 grade is lower, it displays a lower resistance to flow at cold temperatures than the 10W30.
Hence, the 5W30 flows better when it’s cold, making it easier to start the engine and providing quicker lubrication.
The 10W30 has a higher viscosity in cold conditions. It results in slower engine start-up and potential lubrication issues in extremely cold conditions.
Effectiveness in High Temperatures
At high temperatures, the 10W30 offers more protection for the engine components against wear and tear. Both grades have the same second number, so they are equally effective at normal or high-temperature ranges (100°C and higher).
Yet, the 10W30 has a thicker oil film when hot. It offers better lubrication in extreme heat, while the 5W30 becomes even thinner.
Operating Temperature Range
For people who drive in a place with relatively high seasonal temperature variations, the 5W30 will offer more flexibility. As 5W30 and 10W30 are multi-grade oils, they both perform well in a wide range of temperatures.
However, the 5W30 flows smoother in a broader temperature range of -42°C to 30°C. On the other hand, the 10W30 operates well within the -18°C to 30°C temperature range.
Suitability for Engine and Vehicle Types
Although 5W30 and 10W30 graded oils share many similarities, they are typically used for very different vehicle and engine types. The 5W30 is suitable for lightweight vehicles, including passenger cars, SUVs, and light-duty trucks. It’s used in more modern engines with smaller oil passages.
For its thickness, the 10W30 is more suitable for heavier commercial vehicles and SUVs that carry heavy loads. However, it works well with modern engines and regular passenger vehicles as well.
It’s mostly used in older or high-mileage engines as it fills the gap between the moving parts of the engine. In this case, you need to follow the manufacturer’s suggestions to select the right oil.
Fuel Efficiency
According to studies, switching to a lower-viscosity oil can improve fuel economy (by 0.5% to 2%). The 5W30 has a lower viscosity than the 10W30, offering more fuel efficiency. It flows more easily through the engine, reducing friction and resistance.
This means the engine uses less energy to pump the oil around, leading to better fuel economy. Although an average of 1% fuel economy seems like a small amount, it can add up to significant savings over the life of your vehicle.
Pros and Cons of 5W30 Engine Oils
Before you go ahead and purchase a multi-grade motor oil, it’s important to weigh its good sides and drawbacks. So, here are the pros and cons of 5W30 engine oils:
Pros
- Provides great lubrication and protection for engine components to improve its overall performance
- Flows more easily and works well in low-temperature conditions
- Low-viscosity oil which improves the fuel economy by up to 2%
- Highly versatile; works best on passenger cars and modern engines
- Withstands extreme temperatures within the range -30°C to 35°C
Cons
- It is not the best choice for high-performance vehicles that require thicker oil for added protection
- Less effective in protecting older engines from wear
Pros and Cons of 10W30 Engine Oils
Now, let’s take a look what are the advantages and disadvantages of using 10W30-grade oils:
Pros
- Offers greater protection against wear and tear for the moving engine components
- Great for both modern and older engine models and heavy-duty vehicles
- Works well in a wide range of operating temperatures of -18°C to 30°C
- Reduces friction between the moving parts of the engine and enhances their lifespan
- Doesn’t easily break down at high temperatures
Cons
- Not very effective in extremely cold temperatures
Acts slower and less fuel efficient than oils with lower viscosity
FAQs
Got more queries? Let’s take a look at some commonly asked questions regarding 5W30 and 10W30 engine oils.
Q. Is it okay to use 10W30 instead of 5W30?
It’s usually okay to use 10W30 instead of 5W30, except for a few scenarios. If your manufacturer suggests against it and you live in a cold area, it’s better not to use 10W30 instead of 5W30. Using a high-viscosity oil like the 10W30 can also increase drag and result in unusual temperature fluctuations.
Q. Can I mix 5W30 with 10W30?
You can mix 5W30 with 10W30 as both are synthetic oils with slightly different viscosity. However, the thickness, performance, and operating temperature range of the mixed oil will be different from both oils.
Final Verdict: Which One Is For You?
It’s time to settle the 10W30 vs 5W30 debate and decide which one is better. As we’ve discussed, both oils perform great for a variety of engines and temperatures. Yet, 5W30 engine oils are the better choice as they offer a good balance of fuel economy, performance, and protection. If you have a regular lightweight vehicle with a modern engine, the 5W30 is undoubtedly the one for you. However, the 10W30 is also a great option for high temperatures and better protection against wear.