Updated at: 16-07-2022 - By: Lucas

5w30 and 5w40 are two of the most often used grades of engine oil. A wide range of engines can benefit from using these oils due to their universal properties.

All of this information is laid out in detail below, so that you may better understand each type of oil and its qualities, as well as the distinctions between the two.

Because of the labeling’s inclusion of both coefficients (5 and 30 or 40), the oils can be used all year round, no matter the season. These two grades of oil are widely used in automobiles.

Synthetic, semi-synthetic, and mineral car engine oils.

The label or package of the oil will usually include the words.

There are three types of synthetic: full, semi, and mineral.

In current automobile engines, synthetic oils are by far the best option, as they differ from mineral and semi-synthetic lubricants in their processing. In general, synthetic lubricants are more expensive than conventional oils, but they are better able to withstand extremely low and high temperatures and give better protection against engine damage.

The oil lubrication system has a direct impact on the engine’s performance. The question of what engine oil viscosity to use for protection is a common one among many drivers, especially during the chilly winter months. Detailed information regarding engine oils can be found here.

What does 5w30 engine oil mean?

5w40 vs 5w30

SAE 5W30 is a typical type of oil. The Society of Automotive Engineers is known by the initials SAE. Viscosity index at low temperatures is indicated by the symbol 5w. The thinner the oil, the easier it is to start the engine at low temperatures when the number is smaller. A fluidity index of 30 indicates that the oil is able to withstand high temperatures and protect moving parts in internal combustion engines.

Engine oil’s primary function is to keep the engine warm throughout the winter months when temperatures are at their lowest. This ensures that the oil will start and run smoothly, even when the engine is cold. Low-temperature viscosity reduction is the goal, while high-temperature viscosity increase is desired. In this way, you can use the same type of oil all year round.

In addition, it is hoped that the same positive effects would be achieved at higher temperatures.

Single-use or mono-quality oils are engine oils that are only suitable for use in the summer or winter. Additives such as SAE 5 base must be mixed with other engine oil additives in order to provide additional, more seasonal qualities.

At lower operating temperatures, these additives will reduce the oil’s viscosity. However, at higher operating temperatures, they will increase the oil’s viscosity. Because it is a universal lubricating oil, this product provides a wide range of beneficial properties.

Temperatures as low as 35° C are suitable for 5w30 oil ( 31 F). The temperature is currently 35 degrees Celsius (95 F). Many car manufacturers use specific cabs to test the quality of their vehicles. However, the characteristics of the drug that the manufacturer labels on the container may differ dramatically from those that the substance will exhibit under heavy use with an internal combustion engine.

When it comes to oil testing, vehicle dealerships do their tests in the field. It is the purpose of the tests to reveal when the product loses its advantages.

What does 5w40 engine oil mean?

The marks show how the oil performs at high and low temperatures, as I stated earlier. Temperatures ranging from 35 degrees Celsius (31 degrees Fahrenheit) up to +40o Celsius (104 degrees Fahrenheit) can be handled by the 5w40 oil (104 F).

It has been found that some SAE 5w40 viscosity oils can save a significant amount of energy when combined with other criteria. Because of this, it is essential to cut back on oil use by 1.5%. European practice (ACEA, ILSAC) sets a minimum of 2.5 percent as the upper limit for this figure.

The main differences in SAE 5w40 quality:

  • High oxidation stability
  • Increased replacement interval
  • Oil stability
  • Engine cleaning properties

SAE 5w40 specifications and reviews:

  • Minimal engine contamination
  • Increased lifespan due to improved antioxidant properties
  • Reduction of friction in cold weather when the power unit is turned on
  • Evaporation resistance (savings on filling)
  • Reduces engine wear due to simple flow of SAE 5w40 synthetic oil at low temperatures

Under these conditions the engine will not run dry, but the oil will be able to reach all of its critical components, and its service life will be extended. Firstly, how thick the oil is relies on this figure’s size.

The difference between 5w30 and 5w40 engine oil types

5w40 vs 10w40

The viscosity at high temperatures is the most noticeable variation between 5w30 and 5w40.

5W30 is more fluid and less viscous at higher temperatures than 5W40. Since it is thinner than the thicker 5W40 oil, it provides less protection for engine components.

There will be a noticeable difference in viscosity between 5W30 and 5W40. As for starting the engine in the winter, the oil behaves identically, and the difference between these oils is insignificant.

High temperature performance of 5w40 is 12. 5 to 16. 3 mm2/s at 100 g, while 5w30 is 9. 3 12. 6 mm2/s at high temperatures

Oil flow

Higher pressure is guaranteed with 5w40, but flow is reduced.

The thickness of 5w30 and 5w40

5W30 is lighter, which means it consumes less fuel.

Fuel economy

Fuel economy is reduced with 5w40.


Cars of all kinds can benefit from 5w30, but it’s especially good for cold weather. With increased mileage and wear on the engine, 5w40 is a better choice than 5w30 when it comes to high-temperature performance, but it also performs better at lower temperatures.


Costly 5w30 is more common.

5w30 or 5w40. What oil should I pick for my car?

There are many factors to consider while deciding between these two types of oils, including your driving style, the manufacturer’s advice, engine mileage, tolerance, and temperature viscosity.

Many manufacturers recommend using 5w40 oil because of its universal benefits, however 5w30 oil should still be used on new engines until they reach a maximum of 100k kilometers (approx. 63k miles).

5W40 can be used after then since the wear of engine parts begins and they require stronger protection owing to the higher viscosity at operating temperatures.

In modern engines that are subjected to strong loads, many of which include turbochargers, 5W40 oil is suggested. As a result, the engine’s lifespan is extended and the risk of a sudden failure is minimized by creating a durable and dense protective covering.


These lubricants have the same low-temperature properties. Both products have excellent viscosity for cold engine start, as well as excellent viscosity for normal driving conditions.

The lubrication system is more efficient when using 5w30. It cleans the engine parts more effectively, aids in cooling, and reduces fuel use. It’s best to switch to 5w40 oil if the number of gaps in the friction couple rises because this oil can leak, and the engine will be better protected.