Can I Use 10w40 Instead Of 5w30?- [Explained]

A proper engine oil boosts your engine’s efficiency as well as its viscosity. You can’t get better performance from your car if you don’t use the correct oil. Both 10w40 and 5w30 oils can lubricate the engine effortlessly.

So, can I use 10w40 instead of 5w30?

No, you should not use 10w40 instead of 5w30. 5w30 is thinner oil specialized for colder weather. Whereas, 10w40 is way thicker which is suitable for warm weather. Applying 10w40 instead of 5w30 will decrease the engine’s efficiency. It’ll create engine wear and friction, which will damage the engine quickly.

Still not sure? Relax! This isn’t all. We have prepared a broad discussion about the uses of both 10w40 and 2w30 oils.

 If you have a few minutes, join us!

What Are 5w30 and 10w40 Oil?

5w30 oil

Before going into the details, let’s learn some basics. You might not know about these oil types. Hence, we have described them briefly for you.

Starting the discussion with 5w30. 5w30 is an artificially developed oil. It has an efficiency of viscosity level of 5 under lower temperatures. Also, viscosity value of 30 in higher temperatures. 

Compared with 10w40 oil, 5w30 is considered as less viscous engine oil. It’s applicable for both low and high temperatures. 5w30 performs as the lubricant to boost up the efficiency of your engine.

Then 10w40 oil is also an artificially developed engine oil. It provides a viscosity level of 10 under colder atmospheres and 40 under hotter temperatures. Compared to 5w30, this oil is way more viscous under both low and high temperatures.

Key Differences: 10w40 vs 5w30

Differences between 5w30 and 10w40

Measuring viscosity levels under different temperatures, these two are considered differently as per usage. So, we’ve prepared this chart to enlighten you with the key differences between 5w30 and 10w40.

Let’s have a look-

Viscosity LevelHighLow
AtmosphereBest for hot temperature areaBest for cold temperature area
Suitable Engine Appropriate for older model car enginesAppropriate for new model car engines
Sat Down EngineNot suitableSuitable
Lubricating LevelHigh on hotter temperaturesHigh on colder temperatures

Now, we’ll deeply discuss these features right down below. If you’re interested enough, let’s jump into the wagon! 

Viscosity Level

Viscosity measures the oil’s flowing resistance. Higher the viscosity, slower the flow. A higher viscosity indicates less smoothness of your engine’s friction.

Between two of our motor oils, 10w40 has a higher viscosity level. It performs best during hot temperatures as it’s more resistant to flow.

Contrarily, 5w30 oil holds a low viscosity level. A lower rating means smoother flow of fluid. This type of viscosity is more suitable for colder temperatures. 


Motor oil reduces the friction between the engine parts and other parts of a vehicle. If you don’t use any motor oil, engine parts will rub altogether.

The thickness relies on viscosity. A higher oil rating indicates how thick the oil is gonna be. The 10w40 is way thicker than the 5w30 one. So, 10w40 will drag more throughout the engine.

On the opposite side, 5w30 is the thinner one. It can easily move throughout every part of your engine. Also, it works effortlessly when you start up the engine. 


Different types of fluidity work for different situations. Thin motor oil is manufactured to serve in colder atmospheres. 5w30 is a thin fluid that keeps lubricating in low temperatures and boosts efficiency.

Whereas, 10w40 is a thick oil especially constructed for the hotter regions. While driving the car in warm conditions, the thick oil accelerates the engine. 

Suitable Engine and Sat down Engine

As 10w40 is thick motor oil, it’s more applicable for older version engines. Yet it can be used in all sorts of car engines. Thicker oil helps reduce friction and elevates viscosity while driving a car.

Oppositely, 5w30 is suitable for newer model engines. Experts suggest applying this oil for cars with hydraulic tappets more. But we recommend reading your manual requirements to choose the correct motor oil applicable for older car engines.

Lubricating Level

The lubricating level will vary from the thickness of motor oil. Both 10w40 and 5w30 have high-performing lubrication power. But these two will work their best in different scenarios.

While starting up the engine in colder temperature, 5w30 lubricates the engine and maneuvers around the seal. In opposition, 10w40 lubricates the engine when the car is in motion.

So, that’s all the differences between them. 

Can I Use 5w30 instead of 10w40?

You can temporarily use 5w30 instead of 10w40 a few times. Yet it’s recommended to read the manual requirements first then go with the instructions.

The main distinction is in the viscosity level for both lubricants at different temperatures. The smaller the number, the better it will flow.

This indicates 5w30 oil will flow easily at lower temperatures than 10w40. While starting the engine in the winter season, the 5w30 oil will protect your engine. Whereas, 10w40 oil performs well at normal engine operating temperatures. 

[Note: When motor oils remain cool they naturally thicken. Then again, they become thinner while heated].

What Happens If I Put 10w40 Instead Of 5w30 and Vice Versa?

When your car requires a thinner motor oil, using 10w40 is a bad decision. Because 10w40 is a thicker type of oil that can harm your engine’s condition.

Though sometimes interchanging engine oil can show you some benefits. Yet replacing a totally different sort of oil isn’t recommended at all.

5w30 is a thinner type of oil specialized for colder temperatures. A thinner oil authorizes activating the oil during cold temperatures. In a colder situation, oil jamming becomes a real concern for car owners.

In order to do that, a 10w40 oil will not perform as fluently as the 5w30. It will clog the oil and will drop its efficiency level.

Due to colder weather, 10w40 will eventually get thicker. Then it will end up creating problems while starting the engine. Also, the engine will face a lack of fast lubrication, engine wear, and friction.

Similarly, if the car needs thicker motor oil, don’t use 5w30. 5w30 can give your engine fast lubrication, engine wear, and friction. However, for engines that require thicker oil, this benefit isn’t actually that beneficial at normal temperatures.

However, in colder weather using the thinner oil type can be useful. The oil will eventually thicken up a bit. And even if it’s thicker now, you won’t see your engine suffering from oil clogs. This is a very common scenario with 10w40 in cold weather. But with 5w30 you can avoid this. 

Alternative: Can I Mix 5w30 and 10w40?

Usually, engine experts suggest not to mix different oil weights. Because it can be harmful to your engine in a few cases. So, we also recommend not doing so.

Yet, some people have positive opinions about mixing motor oils. They suggest mixing nearly identical multi-grade oils.

If you mix 5w30 and 10w40 together, you’ll get a thinner oil. This thinner oil will uplift the engine’s operational capability in cold temperatures.

Contradictorily, it won’t be healthy for warm weather. Moreover, it will gradually lose its viscose level. Also, it won’t lubricate the engine surface appropriately as before.

So, avoiding mixing these two different types of fluids is a better decision. Yet, the decision is up to you.

[Note: While mixing, use same brand motor oils to prevent engine damage].

Read More-

  1. 5w30 vs 0w20 [Here are the Differences]
  2. Is 10w30 Thicker Than 5w30 [Know The Answer]


Question: When should I use 10w40 oil?

Answer: Well, when you’re driving in high temperatures, go with 10w40 oil. Because it can bear upto 104 degrees Fahrenheit. It can operate under a working high-temperature situation. Temperatures higher than 90 degrees Fahrenheit are a suitable situation for this oil.

Question: Can I go from 10w40 to 5w30?

Answer: The answer is no. You must not degrade the oil from 10w40 to 5w30. 10w40 is more efficient for your car. Whereas, if you shift to 5w30, it will make the engine lose lubricity. Also, it increases engine wear and friction on your car.

Question: Does 10w40 hurt a 5w30 engine?

Answer: Yes, definitely it can harm the engine. You should not apply different-purpose oil in your vehicle. The 10w40 oil is too thick for your 5w30 engine. It will end up hurting the engine. Thus, the engine won’t be able to perform like before.


Hopefully, we provided all the necessary info for can I use 10w40 instead of 5w30? Try to read out your manual requirements first. Then go with directions on which oil is suitable for the car engine.

Remember, it’s always best to go with the oil that suits your car engine and makes it perform well. Otherwise, there’s a high risk of damaging the engine. And to fix your car engine, you have to pay a lot of money.

Well, that’s pretty much all the advice we could give. Good luck!


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