Do you rely on your mechanic when you want to change the engine oil of your car? We would suggest doing your research because nobody takes care of your car better than you. No need to go too far for research, this article can save a lot of your time.

Knowing what’s best for your car’s performance will save you a lot of maintenance costs and will improve its performance to a great extent.

Is it 5w30 or 5w40? Which one is better for your vehicle? Before you decide which one is better, we suggest you know the importance of choosing the right engine oil.

Why is it important to choose the right engine oil?

Like having the right diet is essential for us, it is just as important to feed the right engine oil for automobiles. It prolongs the life of your automobile. It is because engine oil lubricates the parts of your engine so that they do not rub against each other, which may result in wear and tear of the parts. Also, the wear and tear still happen when you use the wrong oil.

You need regular oil changing because it replaces the old dirty oil, which is not quite effective in cooling down the engine and lubrication.

Selecting the right oil can certainly decrease the frequency of your visits to the service station. The wrong choice of oil can cost you much more than the cost you would try to save while picking a cheap engine oil.

Factors to consider when picking the right engine oil

Oil Viscosity

Engine oil viscosity is the ease at which the engine oil pours at a specific temperature. The thicker the engine oil, 5w30 vs. 5w40 in 2020the more viscous it will be and vice-versa. A number represents the viscosity of the engine oil. For 5w30 and 5w40, the number is 5, followed by letter W, indicating “Winter.”

Both 5W30 and 5W40 engine oils have precisely the same viscosity number 5 in winter, which is moderately low.  This suggests that the engine oil flows even at low temperatures. Due to its viscosity, it flows smoothly through the engine. It is considered to be good quality engine oil because other engine oils like 20w are not viscous enough to flow in low temperatures. Both of these engine oils viscosity allows it to be distributed evenly throughout the motor, even when it is cold. It thus minimizes the damage and resistance produced by the parts of the engine.


Weather is another important factor that you need to consider while determining the engine oil that you use for your car. In a low-temperature area, you will need an engine oil that has a lower viscosity. The engine oil should flow easily through the engine system, ensuring the high performance of the engine. This is the reason 5W30 and 5W40 are considered good for colder temperatures.

However, if you live in a high-temperature area, you will need engine oil with high viscosity. Nevertheless, it should not be too viscous because it affects fluidity. High viscosity will make the oil too thin to work as a lubricant, thereby negatively affecting the car parts.


This is the most common engine oil used in vehicles. This engine oil can be used in different automobile engines and is quite effective at a wide range of temperatures. It’s adaptability to different temperatures makes it more popular among users. However, it is preferred more in winters.


This engine oil is not as popular as 5W30, but it has its own advantages. This engine oil enhances your engine’s performance and keeps it up and running for a long time. It also helps the engine to prevent the formation of sludge and other dirt buildups. The 5W40 engine oil can easily move to the other parts and thus proves to be quite useful in greasing and lubricating the engine.

5W30 vs. 5W40

Similarities5w30 vs. 5w40 in 2020

First, let’s see how both of these engine oils are similar –

How 5w30 is different from 5w40?

The most significant difference between the two engine oils is the viscosity of these oils in hot temperatures.

While 5w30 is much suitable to use in cold temperatures, the 5w40 is better for hot temperatures.

Low Shear Rate Viscosity

The 5w30 has a viscosity range of 9.3 to 12.5 millimeters square per second at 100 grams, while that of 5W30 has the range of 12.5 to 16.3 millimeters square per second at 100 grams. Both of these engine oils are represented by number 5 when it’s cold, but both have differences in their grading. The 5W30 is 30 grade, and 5W40 is 40 grade at working temperatures. The 40-grade oil has a higher viscosity than 30 at higher temperatures, which increases the performance of the engine and hence to the proper working of the vehicle.

Temperature Range

While 30-grade oil works best between the temperature range of -25° C to 25° C, the 40-grade oil can be used in the temperature range of -25° C to 35°C.

High shear rate viscosity

For 40-grade engine oil, the high shear rate is a minimum of 3.5 at 150 grams, while for 30-grade oil viscosity, the shear rate is a minimum of 2.9 at 150 grams. This shows how well the oil can stand the heavy load.5w30 vs. 5w40 in 2020


The 30-grade oil is more fluid than the 40-grade oil but provides less pressure than 40-grade oil.


5W30 provides a more fuel economy than 5W40.


5W30 can be applied in different kinds of vehicles with different ranges of working temperatures. However, it is much more suitable for cold climates. On the contrary, the 5W40 works best in warmer temperatures.


The 30-grade oil is lighter and thinner than 40 grade, which results in effective fuel consumption.


5W30 is more expensive than 5W40.


Now that you know everything about both the engine oils in detail, it should be easier for you, which one will work best for you. Also, it is important to read the manufacturer’s manual before selecting one of these. The manufacturer recommends the oil according to the engine. If you decide to stray from the manufacturer’s recommendation, it can affect your engine’s warranty and condition.

5W30 engine oil is quite popular due to its versatility and ease of availability. However, 5w40 is still equally effective in terms of performance and slightly less expensive than the 5w30.