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5w30 vs.10w30 oil: Pick the right one for your engine!

5w30 vs. 10w30 oil: What makes them different?

Imagine driving a car without an engine? Well, it wouldn’t work-not even in your imagination!

Likewise, an engine without oil is doomed. I hear you ask why? It’s because engine oil is just like an engine’s blood; without it, your car engine won’t function well.

Car engines are prone to friction because they have several engine parts moving all at once. Consequently, if your car engine is not well lubricated, it’ll wear and tear-in no time.

So, an engine oil serves as a “friction-preventing” lubricant. See why you need one?

Now that we have established that engine oil is crucial for your car, we are left with one critical question. Which motor oil is the best? I find that 5w30 and 10w30 are two of the best on the market. But deciding on which one to pick might be Herculean.

But ease up! This article contains all you need to know in picking the best oil!

Do you use a 5w30 or 10w30 oil? Or are you trying to find out which of them is suitable for your engine? Keep reading.

You’ll find:

  • A detailed review of 5w30 and 10w30 engine oil
  • Their distinguishing features

Let’s go into the detail already.

5w30 vs 10w30 comparison chart

Below is a comparison chart that reveals the key features that distinguish each oil type.

5w30 vs. 10w30 oil comparison chart

Oil viscosity explained

The efficiency of engine oils is dependent on one major parameter: viscosity. The viscosity of engine oil is the best description the oil can have. Simply put, it reveals the characteristics of motor oils.

According to the Society of Tribologists and lubrication engineers, viscosity is the most important motor oil property.

Now to the important part, what does oil viscosity mean?

What is oil viscosity?

How about we take this from the top? Just before we explain oil viscosity, let’s delve into engine oil’s meaning to have a better grip on the definition of viscosity.

Engine oil is alternatively called lubricating oil or motor oil. It’s a lubricant used to grease internal combustion engines. Motor oils contain enhanced base oil, used to prevent friction in engines.

The truth is your engine consists of different metallic engine parts, synchronizing each time your car moves. Owing to this fact, internal combustion engines often experience massive friction.

See why you need to keep the engines slick always?

You wouldn’t want your engine’s life span to be abruptly reduced. Well, that’s exactly what a motor oil prevents. Besides durability, it also helps manage your fuel economy effectively.

But the ability of your engine oil to actively perform these functions depends on the oil viscosity. This brings us back to the question of the hour, what is viscosity?

Viscosity means the feature of a fluid– or, in this case, an oil– that dictates its flow rate. Simply put, it’s a term that describes the thickness of a liquid.

The higher viscosity grade, the thicker the liquid, and vice-versa.

Now here’s the deal, the higher the viscosity, the thicker the liquid, and vice-versa.

Here’s a question for you: have you ever wondered what the numeric values “5w30 and 10w30” mean? Well, they aren’t just numbers of the product; they are the oil’s viscosity values.

I bet you didn’t know that!

Sometime in 1950, the Society of Automotive Engineers (SAE) introduced a new numeric code structure to grade engine oils based on their viscosity level.

Hence, 5w30 and 10w30 are numeric codes that symbolize the viscosity or thickness of oil at varying temperatures. However, the thickness (Viscosity) of “some” engine oils changes with the temperature.

That’s why there are two different values (i.e., 5w and 30): one for cold weather and the other for an engine’s operating temperature (hot). In contrast, some motor oils have a single value and a static oil consistency. These types of oils are called Singlegrade.

While the ones with two viscosity values are Multigrade oils, they contain a viscosity index improver, making the oil thickness adjust to weather conditions.

Want to find out more about the single grade and multigrade oils? You are just about to find out.

Singlegrade oil vs. multigrade oil

The major difference between Single grade and multigrade oil is pretty simple. The former has just one viscosity grade, while the latter consists of two.

The two viscosity grades of multigrade oils depict the flowability in cold and warm weather. A perfect example of multigrade oil is 5w30 and 10w30 oils. These oils come out thinner at a cold temperature but switch to thicker consistencies in an operating temperature.

However, single-grade oils aren’t suitable for cars; they are often used for land mowers. On the other hand, multigrade oils are best suited for vehicles because their viscosity changes and adjusts to weather conditions.

Numbers explained in oil viscosity

Remember the viscosity values I mentioned earlier? They are also called SAE numbers or viscosity grades.

However, each number is crucial to engine oil efficiency. So, it’s important to understand what each value means before you purchase an engine oil.

Let’s start with the letter “w” in the middle of the numbers. “W” here means “winter.” The letter often accompanies the first number; it indicates the oil’s consistency in cold weather. The last two digits after the letter, on the other hand, depict the flow rate of the oil at 100 degrees Celsius.

For instance, the “5w or 10w” in these oils are the SAE numbers that indicate the oil’s performance in low temperature. While on the flip side, “30” is the SAE number for hotter temperatures.

Well, the SAE numbers aren’t just forged or guessed via the oil’s appearance; they are accurately deduced from a “J300 test.” A J300 test is a viscosity test conducted with a Rotary viscometer or, most often, a capillary tube viscometer.

J300 test through viscometer

Oil viscosity chart

Below is an oil viscosity chart graphically portraying the diversity of 5w30 and 10w30 oils.

The 5w30 flows more freely at cold temperatures because it’s thinner

This chart reveals the SAE measurement at a cold temperature (represented by the readings above) and the operating temperature measurement.

It reflects the oil’s flowability at low and at rising temperatures. It also indicates that a high-temperature viscosity is often tested at 100 degrees C. This is because it’s considered the working temperatures of engines.

Furthermore, the bars’ right side indicates thick consistency, while the left side represents thin consistency. 

Considering this chart’s readings, the 5w30 flows more freely at cold temperatures because it’s thinner. Contrarily, 10w30 oil is slightly thicker; hence the flow is slower in low ambiance.

Here’s a quick tip: your engine oil needs to be thin enough to lubricate your car engine in low weather conditions properly.

Differences between 5w30 and 10w30

Here are the main differences between these two oils.

Viscosity grade

A viscosity grade can either be multigrade or monograde (single grade). Since we have established that the two oils in question are multigrade, let’s move on to the critical part.

What’s the difference between their viscosity grades? Quite frankly, the difference is mild but crucial.

For 5w30, the winter viscosity grade is 5, making it less dense in comparison with 10w30 Oil. 10w30, on the other hand, has a viscosity of 10 at low temperatures. However, their high-temperature viscosity grades are both 30.


At operating temperature, the two oils have the same thickness. But in low ambiance, 10w30 is thicker than 5w30 Oil. This is due to its higher viscosity in low temperatures.


While these two oils are quality, they thrive better under different conditions.

Here’s what I mean…

If you live in Northeastern USA, for instance, you might want to think twice before purchasing 10w30 Oil. You shouldn’t consider it because it wouldn’t perform at its best. In this case, 5w30 Oil is best suited.

Well, according to SAE, if a temperature is lower than -22 degrees F, a 10w oil will hit a complete pumping failure. So, for maximum performance in cold regions, trust 5w30 to lubricate your engines efficiently.

Contrarily, if you live in Arizona, USA, for instance, you can use both 5w30 and 10w30 oil. Arizona is warm-all year long. Since both oils’ viscosity is 30 at working temperatures, they’d perform similarly in hot regions like Arizona.

Cold flowability

The cold flowability of these two oils is yet another significant difference. During cold startups, a 5w30 oil flows faster than a 10w30 oil. Hence, if you need an oil that flows well during cold temperatures, go for 5w30.5w30 vs. 10w30, which is better?

This is dependent on two main factors — where you live and the manufacturer’s recommendation for your car.

We’ve established that 5w30 is suitable for cold regions. However, the owner’s manual of your car determines the best oil for your car engine.

But generally, considering versatility, the 5w30 oil is superior to 10w30 oil. Well, here’s the deal, you can use a 5w30 in both hot and cold ambiance, but a 10w30 is more suitable for hot weather.


What happens if you put the wrong oil in your car?

Using the wrong oil in your car can result in different complications. In the long run, it could damage your engine. Most often, when you use a lubricant with extremely high viscosity, it lubricates your car poorly.

So, to avoid causing any major harm to your car engine, it’s safer to use the lube oil recommended by your car manufacturer.

Can you use 5w30 instead of 10w30?

This is mainly dependent on your manufacturer’s recommendation and the climatic condition in your location. If you use Oil that’s much lower in viscosity than necessary, the Oil will wash off as soon as the car starts moving. This can lead to serious friction and the wearing of the engine in the long run.

Similarly, using extremely viscous oil can lead to a distorted flow of Oil to essential organs. It can also lead to a defective heat transfer.

Hence, the answer to whether you can use a 5w30 instead of 10w30 is relative. But, yes, you can, if it’s a better choice.

Can I mix 5w30 and 10w30?

Mixing two different oils is only acceptable or safe when the two oils have similar viscosity. In this case, 5w30 and 10w30 are pretty similar.

Consequently, you wouldn’t be tampering with your engine by mixing them. One will simply be topping up the other. So yes! You can mix the two oils.

5w30 vs. 10w30? Which is better for an older engine?

While both oils are outstanding lubricants, it’s obvious that your location’s ambiance is of great importance. Although for old motor, it’s a question of which Oil is considerably thicker. Hence, 10w30 Oil is a better choice here. This is because slightly thicker oils aid practical sealing ability for old engines.

Final words

One main difference between 5w30 and 10w30 is the cold flowability/ thickness. While they are both highly effective, 5w30 beats 10w30’s performance in cold regions. I strongly recommend 5w30 oil for low ambiance regions.

So, which one is best for you?

Well, let’s put it right on the table; 5w30 is a preferred choice.

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