Is 10w30 Thicker Than 5w30? [Mystery Solved]

It is always a very confusing and concerning thing to choose the best engine oil for your car. While choosing the oil you might think that switching to thicker oil can improve engine service. But before any of that, you should know which is thicker.

So, here’s a question: is 10w30 thicker than 5w30? 

Yes, in super cold weather or temperatures 10w30 is the thicker oil type. Because 5w30 is much thinner when the temperature is really low. But in general temperature or in the operating temperature both the oil have the same thickness. Both of the oils have the same level of grade and the same level of viscosity. 

Everything still seems super confusing to you? We understand. But don’t worry we have discussed everything in detail. 

So, let’s jump up to the details, shall we?

2 Things to Consider Beforehand

If we want to continue our debate, it is 10w30 thicker than 5w30. First, we need to know about the SAE grade along with the viscosity of these two oils. Then we can conclude our debate as a result. 

What is SAE grade?

The full form of SAE refers to the Society of Automotive Engines. SAE develops a grade for both motor oil and transmission oil. For example 0w20, 10w20, 10w30, 5w20, 5w30. 

SAE numbers are used in connection with recommendations for synthetic oil. This number represents the viscosity at cold temperature and viscosity at hot or operating temperature.

Take note of a “W” grade oil. The word W refers to the winter. In other words, you can say this oil of “W” grade was tested at a cold temperature. A viscometer is mainly used for determining your oil’s viscosity at a different temperature.

A high viscosity number indicates thicker oil. Because they will take a long time to flow through the viscometer in testing.

The viscosity range of one oil can be changed so the centistoke is taken into account. Centistoke more accurately shows the viscosity of the oil. Now, you should focus on having the right idea on viscosity. 

What Is Viscosity?

Viscosity denotes the resistance of the fluid. It also refers to the opposite of fluidity.

Viscosity might be considered as internal molecule friction.

Velocity is basically the main aspect that determines your oil’s grade. 

If you use a low viscosity oil then it means it will flow much more than a high viscosity oil. So, it will be easy to start your car’s engine. But high viscosity oil acts as a lubricant as well. 

So, a higher viscosity oil will protect the engine more than a lower viscosity oil.

SAE grade mainly denotes the viscosity of oil examined in different temperatures. Therefore, you should choose your engine oil to determine what you need. Keep in mind the weather condition and your engine’s friction.

5w30 Vs 10w30: Which Oil Is Thicker?

Now, if you notice the two oil types’ names, you will see the key differences. These names are the SAE grade of this oil and it denotes viscosity. Or in other words, it also denotes the thickness of the oil.

In the case of 10w30, you can tell the viscosity of the oil. Which is at a lower temperature of 10 and at an operating temperature of 30. In other words, it also means that the oil is thicker at the operating temperature.

For 5w30, the viscosity of the oil according to SAE grade is 5 in lower temperatures (-18 degrees celsius). As well as the viscosity in the operating temperature is 30.

If you compare both oils, you will notice that the thickness is the same in the operating temperature. Both the oil have the same temperature at operating temperature (100 degrees celsius).

But the oil types have more differences. That’s why if you want to pick one between the two, you need to compare some other features also. 

10w30 Vs 5w30: Which Oil Type Is Better?

Curious about the two oil types even more? Well, let’s check some more basic differences-


API SN is basically an engine oil category. It is introduced by the American Petroleum Institute to examine the oil in different specifications. Mainly the code SN means for the vehicle produced after 2010.

The API SN has some requirements on fuel consumption, sludge control, and sludge at higher temperatures. Both the 5w30 and 10w30 meet the API SN requirement.

So, as per API SN they both are good to go with any car that is produced after 2010.


From the grade of both oils, you can say the performance of both is the same. But 5w30 has a slight advantage in performance.

5w30 will flow more smoothly than 10w30 in extremely cold weather. 10w30 can operate from -18 degrees celsius to 35 degrees celsius. On the other hand, 5w30 can operate from -30 degrees celsius to 30 degrees celsius.

It will be easier to start up the engine with 5w30 than 10w30 in extreme weather. Because the oil would be more fluid at that temperature.

Fuel Economy

Both 5w30 and 10w30 have the same level of fuel economy as per API SN. Because both of the oils have the same level of viscosity. The similarity is at the general temperature and operating temperature.

So it can be a similarity rather than a difference in this fuel economy sector.

Both the oil have the same performance and velocity in general terms. You might be thinking what if we mix both 10w30 and 5w30. 

Can I Use 5w30 Instead Of 10w30?

Well, in cold weather it’s better not to. Because in that temperature the thickness level between the two oil types isn’t the same. The 5w30 is a little bit thinner than the 10w30 in the cold temperature.

But you can avoid that because of the extreme temperature. So, as for operating temperature or general temperature 10w30 and 5w30, both have the same thickness. Therefore, you can use 10w30 instead of 5w30.

What Happens if I Put 10w30 Instead of 5w30?

If you use 10w30 in place of 5w30 at operating temperature, nothing bad should happen. Because they both have the same thickness at that temperature.

But in extremely cold weather, you have to stick to 5w30. Because 10w30 will get thicker at that temperature. As a result, your car engine might not function how you want it to. The car can even stop during you’re driving it due to oil clogging in the engine.

So, keep the weather in mind and use the oils accordingly that.

Can I Mix 10w30 to 5w30?

Mixing two different oils is not available but still, some drivers do that. Because there is no result affecting the engine yet. 

But apparently, 10w30 and 5w30 have different velocities and different additives. So, when you mix both oils they will not blend that much.

Pouring 10w30 to an engine that was running on 5w30 poses no harm. But still, you should be very careful about your automobile engine restriction.

Here’s a catch: the viscosity of both oils is the same in general temperature. Thus, it will blend well. That’s why it’s okay to say it’s alright to mix 10w30 to 5w30.

However, you should know that it’s beneficial to use only one oil for your engine. Poring one oil to your engine offers more benefits than a DIY mix or regular change between oil types.

Mixing might not cause any harm to your engine but it won’t get any help either. So you might be wondering about an alternative oil. 


Question: Do high mileage engines need thicker oil?

Answer: High mileage oil docent hurts and it is intended to prevent leaks from starting. Some machines recommended switching to thicker oil or high viscosity oil.

Questions: What happens if engine oil is too thick?

Answer: If your engine oil is too thick, you will notice your engine might start to tick. The noise gradually starts after starting the engine. What you are hearing is metal parts hurting each other as there is not enough lubrication.

Question: Does thinner oil warm up faster?

Answer: Thinner oil flows quickly to every part of the engine at cold temperature. And it lubricates critical engine parts faster than thicker oil. 


Hope now you know the answer for is 10w30 thicker than 5w30. Are you all cleared? If so, let’s check out an important tip.

You might have an old car. And you might want to change your car oil for better mileage. If so, you can always go for the thicker oil. But you should know that most automotive companies use thinner oil with new cars. 

Best of luck with your car.

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