5w30 Vs 10w30: Detailed Comparison

The most common motor oils used in modern engines are 10w30 and 5w30. However, many car owners do not know the difference between them. 

This article explains what differentiate 5w30 from 10w30 motor oils. It also provides comprehensive information on choosing the perfect motor oil for your car engine.

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 5W20, 5W30, 0W40, 10W30, 10W40, 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, 5W30 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 10w30 and 5w30 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 10w30 and 5w30 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.

5w30 vs 10w30 comparison table

Viscosity

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, 5w30 would flow easily in cold temps because it has a lower viscosity than 10w30. 5w30 helps for cold-starting and performs better than 10w30 in Winter. 

However, when an engine is started at normal operating temperature, both 5W30 and 10W30 would flow at the same rate because they have the same viscosity rating for hot temps.

Application/ When to Use

5w30 is the best to use during Winter because it is thinner, and would flow more easily than 10w30. Also, 5w30 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, 10w30 is the right oil to use. Also, for heavy-duty applications (trucks, towing, etc.), whether in cold or hot temps, 10W30 would perform better due to its thickness over 5w30.

Fuel Economy

Both 5w30 and 10w30 can help improve fuel economy depending on the season, and application. However, 5w30 would easily get to the hard-reach areas of an engine than 10w30; this means more fuel efficiency. 

That said, comparing 10w30 and 5w30 for fuel economy, 5W30 is the winner, and that’s because it is thinner (flows faster).

Performance

The 5w30 performs better in cold temperatures – during Winter – and it improves engine efficiency. On the other hand, 10W30 performs well, but it’s not just better than 5w30 in cold temps because it is thicker and flows slowly at low temps. 

Notwithstanding, when you’re driving in extremely hot temperatures, 5w30 would degrade easily (thin out). While 10W30 would deliver a better performance. This is why 10W30 is recommended for heavy-duty vehicles and applications while 5w30 is for regular cars.

Benefit

While the benefits you’d get from an oil depends on the additives included in the formula/base oil, 5W30 oils are typically more beneficial to use than 10W30 oils – especially if you don’t always use your car for towing or other tough tasks.

FAQs

1. Can I Use 10w30 Instead Of 5w30?

Yes, you can actually use 10w30 instead of 5w30, but ensure you’re doing it in the Summer season. If it’s Winter, 10W30 would make your engine perform sluggishly as the thick oil would struggle to lubricate the engine components. In some rare cases, 10w30 may cause engine overheating in extremely cold temps.

2. Can I Mix 10w30 and 5w30?

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 5w30, 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.

Conclusion

10w30 and 5w30 are multigrade oils with the same viscosity for hot temperatures, but varying viscosities for cold temperatures. The 5W30 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.

10W30 is a thicker oil. It is recommended for trucks, towing vans, and other heavy-duty vehicles that are subject to extreme temperature and performance. While 5W30 would save you more fuel in Winter, 10W30 would perform better when driving in scorching temps.

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