No, you should not use 10W-40 instead of 5W-30 doing so will invite a lot of problems to your engine.
Oil grades are recommended for a good reason, that is the well-being of your engine and better performance.
You cannot just swap out a thin oil for a thicker one without any reason.
You can however, use 5W20 instead of 5W30.
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What if I use 10W-40 instead of 5W-30?
Both oils are designed to work efficiently under specific conditions and environments.
The first performs better in a hot climate whereas the second is better suited to cold regions.
If 5W-30 is substituted by 10W-40 it will no doubt affect the performance of your engine, especially in a colder climate.
Not only will it give poor performance in winters, but it may also cause your engine to dry start.
Drawbacks of using 10W-40 instead of 5W-30
Oils are recommended for a reason if these recommendations are not followed you may face certain consequences which are as follows:
Poor Performance in winters
It is obvious that you will face this problem as you are replacing low viscous oil with high viscous one.
You need thin oil in winters for better flow and lubrication so if it is replaced with a thick viscous oil that will cause more friction, leading to more wear.
Overheated Engine
With thick oil being used instead of recommended thin oil the friction between parts of the engine will increase which will lead to the overheating problem.
Wear and tear of engine parts
With high friction and increased temperatures, the wear and tear also increase which may end up shortening the life span of your engine.
Difference between 10W-40 and 5W-30
Generally speaking, one oil is meant to be used in cold climate regions while the other is made to give you better performance in hot temperatures.
As the name suggests 10W-40 having more viscosity is suited for hot temperatures while the other one is for cold temperatures.
Side Note: For better understanding, also check out the differences between 5W-20 and 0W-20.
The comparison between these two Oils in given below:
| Features | 10W-40 | 5W-30 |
| Suitable Climate | Better for hot regions | Better for cold regions |
| Old Engine Compatibility | Not suitable | Suitable |
| Best Lubrication | At hot temperatures | At cold temperatures |
| Temperature Range | -25°C (-13°F) to 40°C (104°F) | -30°C (-22°F) to 35°C (95°F). |
When to use 10W-40?
When you are driving in regions with hot temperatures you should go for 10W-40 as it can provide good performance on temperatures up to 40°C (104°F).
You may also use it if your car is too old that is at least 10-15 years old, as old engines tend to heat up quickly and this oil provides better performance in the high-temperature range.
Side Note: You can also use 10w40 instead of 10w30.
When to use 5W-30?
This oil is better suited for cold temperatures, thanks to its low viscosity it can work in freezing temperatures and provides good oil flow and lubrication.
It is always recommended that you use this oil if suggested by the user manual to achieve better fuel economy.
Your guide towards better engine oils choice:
Viscosity
Low viscosity oils are better suited for cold temperatures whereas for hot temperatures thick oils are a better choice.
Temperature Ranges
Engine oils tend to work best within its specified temperature range due to the type of blend used to manufacture them.
Manufacturer Recommendations
Manufacturers recommend Engine oil grades after a lot of testing and consideration.
They are well aware of the extent of their product hence sticking to their recommendations is always better.
Climatic Conditions
Temperature and climate play an important role in the performance of engine oil.
The lower the cold viscosity, the better the oil is for cold climates, and the higher the hot viscosity, the better the performance will be in hot climatic conditions.
Engine type and condition
The engine type is also what matters in selecting your engine oil. Old engines tend to heat up rapidly, so there is no need to keep using oils that were meant to perform at low temperatures.
Therefore, thick oils are better suited for them.
Final Thoughts
We will always recommend using the specified oil grade in the manufacturer’s manual.
It is said “you should not make a decision if you don’t necessarily have to”, so if for some reason you are not getting the desired performance from your specified oil you may change it under the following conditions
- Your engine is very old.
- You are driving in hot climate regions.
- Your engine is more powerful.
