The most common motor oils used in modern engines are 10w-30 and 5w-30. However, many car owners do not know the difference between them.
In general, 5w-30 oil is best used for passenger cars, SUVs, and other cars that are not used for heavy-duty applications. Meanwhile, 10w-30 oil is recommended for trucks, towing vans, and other heavy-duty vehicles.
But that’s not all!
Read on as I will unfold the difference between these oils in this article regarding performance, fuel economy, and when to use them.
Let’s get started!
Oil Numbers Explained
Single Oil vs Multigrade Oil
Put simply, a single oil (or single-grade oil) is an oil with one viscosity rating. An example of such oil is SAE30 motor oils. Single oils are used in machines and engines that are not subject to varying temperatures (normal operating temperatures 212 °F).
Multigrade oils are the best-recommended oils for motor engines. They have dual viscosity ratings for cold and hot temperatures, respectively. The viscosity ratings of multigrade oils are demarcated with the letter “W,” which stands for “Winter.” Examples of multigrade oils include 5w-20, 5w-30, 0w-40, 10w-30, 10w-40, and more.
Numbers and Letter “W” in Multigrade Oils
The first number represents the oil’s viscosity in “Cold Temperatures,” while the second number stands for the oil’s viscosity in “Hot/Operating Temperature.” The letter “W” itself represents “Winter.”
For instance, 5w-30 means that the oil you bought has a viscosity rating of “5” in cold temperatures (below 45 °F). Meanwhile, the viscosity rating of “30” (SAE30) in hot temperatures (normal engine operating temperature 212 °F ).
10w-30 vs 5w-30: Key Things in Common
They are Both Multigrade Oils
From my detailed explanation above, it’s clear that 10w-30 and 5w-30 are multigrade oils because they have dual viscosity ratings for cold and hot temperatures, respectively.
They are Both SAE30 Oils
Both oils have the same viscosity rating for hot temperatures (normal engine operating temperature). This implies that 10w-30 and 5w-30 would flow at the same rate when the car is already started and running.
However, although they’d flow evenly, the performance would depend on the additives used in the oils’ formulas respectively. Every motor oil manufacturer uses special additives to make their oils perform better than that of their competitors.
10w-30 vs 5w-30: Head-to-Head Comparison
Now, let’s look at the differences between these two oils. This comparison would help you identify the most suitable one to use for your engine.
As explained, viscosity is the rate at which a motor oil flows in cold and hot temperature. An oil with a lower viscosity rating would flow more easily and faster than that with a higher viscosity rating.
In this case, 5w-30 would flow easily in cold temps because it has a lower viscosity than 10w-30. 5w-30 helps for cold-starting and performs better than 10w-30 in Winter.
However, when an engine is started at normal operating temperature, both 5w-30 and 10w-30 would flow at the same rate because they have the same viscosity rating for hot temps.
Application/ When to Use
5w-30 is the best to use during Winter because it is thinner, and would flow more easily than 10w-30. Also, 5w-30 is specified for most modern cars, SUVs, sedans, and other cars that are light-duty applications.
However, during the Summertime, or if you live in high temps regions, 10w-30 is the right oil to use. Also, for heavy-duty applications (trucks, towing, etc.), whether in cold or hot temps, 10w-30 would perform better due to its thickness over 5w-30.
Both 5w-30 and 10w-30 can help improve fuel economy depending on the season, and application. However, 5w-30 would easily get to the hard-reach areas of an engine than 10w-30; this means more fuel efficiency.
That said, comparing 10w-30 and 5w-30 for fuel economy, 5w-30 is the winner, and that’s because it is thinner (flows faster).
The 5w-30 performs better in cold temperatures – during Winter – and it improves engine efficiency. On the other hand, 10w-30 performs well, but it’s not just better than 5w-30 in cold temps because it is thicker and flows slowly at low temps.
Notwithstanding, when you’re driving in extremely hot temperatures, 5w-30 would degrade easily (thin out). While 10w-30 would deliver a better performance. This is why 10w-30 is recommended for heavy-duty vehicles and applications while 5w-30 is for regular cars.
See Also: 5w-20 Vs 5w-30: Head-to-Head Comparison
While the benefits you’d get from an oil depends on the additives included in the formula/base oil, 5w-30 oils are typically more beneficial to use than 10w-30 oils – especially if you don’t always use your car for towing or other tough tasks.
1. Can I Use 10w-30 Instead Of 5w-30?
Yes, you can actually use 10w-30 instead of 5w-30, but ensure you’re doing it in the Summer season. If it’s Winter, 10w-30 would make your engine perform sluggishly as the thick oil would struggle to lubricate the engine components. In some rare cases, 10w-30 may cause engine overheating in extremely cold temps.
2. Can I Mix 10w-30 and 5w-30?
A lot of drivers mix motor oils of similar viscosities. Yes, it won’t hurt their car engines, but it’s not a recommended practice. When you mix motor oils, you deprive your engine of enjoying the full benefits both oils would have delivered if used separately. That said, you can mix 10w30 and 5w-30, but it’s best to use one out of the two.
3. Should I Use Thicker Oil In An Older Engine?
Yes, thicker oils are recommended for older engines. Using a thicker oil than what’s specified for your engine would lead to poor fuel efficiency. However, older cars need thick oils to prevent excessive wear and leaks on the “already old” engine components. So, you could go for a “High Mileage” oil instead if your car has over 75k miles in its odometer.
See Also: 0W-20 Vs 5W-20: Detailed Comparison
10w-30 and 5w-30 are multigrade oils with the same viscosity for hot temperatures. But they vary viscosities for cold temperatures.
The 5w-30 is thinner and flows faster in cold temps; it is best for passenger cars, SUVs, and other cars that are not used for heavy-duty applications. This oil grade would save you more fuel in Winter.
10w30 is a thicker oil. It is recommended for trucks, towing vans, and other heavy-duty vehicles subject to extreme temperature and performance. If you are driving in scorching temps, this oil grade performs better.
Could you share with us which oil grade you are using now?