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Is 10w30 Thicker Than 10w40? Major Differences | 10w30 vs 10w40

10w30 vs 10w40, before discussing differences we need to understand few things that both are the most common categories of engine oils that people use nowadays, basically, an engine oil lubricates all the parts of an engine and ensures that they are running smooth and reduce friction between them. So you can see how vital tasks it is performing and therefore it is very important to choose which oil to use in your engine wisely.

Further, we are going to discuss that among 10w30 vs 10w40 which oil will be suitable in which situation.

The number 10 in the names denote the ease of pouring the oil in cold conditions which are same in both the oils so we will give more emphasis on the second terms which are 30 and 40, they denote the ease of pouring oil in working conditions in simpler language more the number more is the viscosity of the oil, as the oil 10w30 will have less viscosity and will be thinner while on the other hand, the oil 10w40 will be more viscous and thicker than the 10w30.

Now we will see which oil will be better in which conditions 

The factors we will going to look upon are:

  • Weather conditions
  • Type of the vehicle
  • Cost and Fuel efficiency

Weather Conditions

The temperature of the environment in which a vehicle is running contributes a lot towards working of the engine of a vehicle and it directly affects its efficiency. Likewise, the temperature is also a factor to decide which engine oil to use.


As we have already told you above that the viscosity of 10w30 engine oil is less than 10w41, hence it is easy to flow and thinner in texture. 10w30 oil  is suitable to use in cold weather conditions because in such conditions the oil will only get heat from the engine not from the external environment and thus it will not get more thinner and therefore it will be perfect for such conditions, on the other hand, if you will try to use 10w40 in such conditions then the oil can face problem in flowing through the parts of the engine as it is already very thick.


Since the viscosity of the 10w40 oil is greater than the viscosity of 10w30, it is thicker and therefore it is more suitable to use in hot weather conditions because in a hot environment an engine oil will have to bear the heat of engine as well as of the atmosphere which will make it thinner than its original form and this is the reason for not using 10w30 in hot temperature as it is already very thin and can become more after the influence of more heat.

Now I think you are smart enough to understand which oil you should use according to the temperature of the surroundings you are using your vehicle in.

Type of Vehicles

The design of a vehicle also plays an important role in deciding the type of oil to use.


The vehicles of the new generation are made of more advanced and cool technologies, and because of it their passage not get affected easily with time which means they will not expand and will remain of the same size and they will also not wear out, and for the engine of such vehicles using 10w30 oil will be more relevant as it will flow in the passages more easily because of being thinner.


If you have a vehicle of old design than with time its oil passages will wear out and also expand and therefore oil with high viscosity will be more suitable to use and keep the parts running in proper conditions. So if you have an old bike then consider using 10w40 oil in it.

Cost and Fuel Efficiency

This factor can be important for some of you while some of you will not care about it and lay more emphasis on the better working of your vehicle engine, and to be more precise it depends on you which oil to use per your budget for the oil. 


So the best part of using 10w30 oil is, it more readily available in the market and is cheaper to purchase plus it is more cost-efficient because it keeps running the parts of the engine more smoothly thus producing less resistance between the parts and less resistance means the vehicle will have to use less power in running properly and that results in consuming lesser fuel which in turn will save your lot of money.


The 10w40 oil is quite expensive than 10w30 as it is not readily available in the market, but there are other more advantages of using 10w40 which make it costlier.

Note: Do not make cost a priority, use the oil which will benefit your vehicle in the long run and also according to the factors that we have already discussed above in the article.

Frequently Asked Questions [10w30 vs 10w40]

Question 1: What are the most important functions of engine oil?

There are various functions of an engine oil which makes its choice an essential task

  • Engine oils clean the internal components of a motorcycle by suspending the contaminants in it and not letting them stick to the components.
  • The most important function of engine oil is to reduce the resistance between the parts of the engine by forming a protective coating on them.
  • Engine oil also cools down the temperature of the components by absorbing heat from them.
  • It protects the components from corroding by making a barrier between components and corroding materials.
  • Engine oil also absorbs all the mechanical shocks.
  • It acts as an excellent energy transferer.

Question 2: What are some best engine oils for greater mileage?

Some of the best engine oils for greater mileage are:

  • Castrol GTX High Mileage Synthetic Motor Oil.
  • Pennzoil High Mileage Oil.
  • Valvoline High Mileage Motor Oil
  • Mobil 1 High Mileage 5W-30 Motor Oil. 
  • Castrol High Mileage Advanced Full Synthetic Motor Oil.
  • AmazonBasics High Mileage Motor Oil.
  • Royal Purple High-Mileage Synthetic Motor Oil. 
  • Mobil 1 High Mileage 5W-20 Motor Oil.

Question 3: How will I know that engine oil needs replacement?

  • The most simple way to find when your motor oil needs replacement is to look at the oil change sticker present on your vehicle, mechanics put the oil change sticker at the time of service at the driver’s side of the car.
  • Check the color of the oil, fresh oil is of golden color, but with time the color of the oil changes, and it will seem to be dirty. So keep on checking the color of the oil and if it looks dark then consider changing it. 
  • If engine oil is not doing its work properly it means it should change, you will find this when you will hear different noises from your bike as the bad oil can fail to reduce resistance between the components and they will rub against each other.
  • There is an oil check light that is present on your dashboard, it is red in color, this is the simplest indication that you need to change your engine oil. 

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