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5w40: Choosing the Right Engine Oil for Your Car

When choosing an engine oil for your car, there are two things you need to take into account- the temperatures in your region and the vehicle manufacturer’s recommendations. The 5w40 engine oil is a versatile oil thanks to its operability across a wider temperature range.

What does 5w40 mean?

5w40 is the grade of the oil. The ‘W’ in the oil grade stands for winter. The figures on either side of the ‘W’ are the viscosity grade of oil at the temperature extremes. The number to the left indicates the viscosity of the oil at 0°F or -17.8°C, while the one on the right indicates the oil’s viscosity at 100°F or 212°C.

In case of 5w40 car engine oil, the viscosity at cold temperatures is 5, which means, it is less viscous, as compared to a similar oil, for example, 10w40 at the same temperature. The hot viscosity of 40 indicates that the oil is less viscous than other oils such as 15w50 at higher operational temperatures.

Why does the viscosity of the engine oil matter?

The viscosity of a fluid can be defined as its resistance to flow. This property of the oil helps in lubricating your engine parts and protecting them from wear and tear, along with flushing out impurities and carrying away heat. An oil that is too viscous will not flow properly in the engine. It can even cause some moving parts to get stuck. If the car engine oil is too thin, it won’t be able to coat the engine parts and protect them from wear and tear. Also, the viscosity of oils changes with temperatures- increasing with a drop in temperature and decreasing as the temperature rises. Therefore, the viscosity of a car engine oil plays an important role.

You might have to choose between performance and protection of your engine parts when selecting a car engine oil. A more viscous oil will protect your engine’s components but might reduce your engine performance, as the engine needs to do more work to overcome the resistance of the oil. Therefore, it is essential to read your manufacturer’s recommendations carefully before choosing an engine oil. Other factors include the daily temperatures and the climate in your region, the driving conditions, and your usage.

What should I go for- 5w40 or 10w40?

Now that you know why you should be careful when selecting an engine oil for your vehicle, you might end up thinking about whether to go for 5w40 or 10w40. As you can see, the hot viscosities of both oils are similar. This means that they are equally efficient in protecting your engine at high temperatures. The only difference between these two oils is the cold viscosity. A viscosity grade of 5 means that the oil will flow more easily as compared to 10w40 at cold temperatures. Therefore, it can help in starting your car after a cold night. Hence, if you live in a region where you commonly encounter cold weather, it would make sense to go for 5w40 car engine oil.