10W30 vs 10W40 – Differences in Engine Oil Viscosity

Have you ever wondered about the meaning of the number printed on the engine oil can? The article will discuss 10W30 vs 10W40 – differences in engine oil viscosity

10W30 vs 10W40

Engine oil - SAE: 10W-40

Under the market mechanism, the more new brands of engine oil appear, the more consumers will gain, and there will be more choices. With the development history of the lubricant industry more than 100 years ago, it was first invented in one of the cradles of the Soviet mechanical engineering industry and then improved in other developed countries such as the United Kingdom, Germany, France, the US, etc.

However, the lubricant industry in a developing country is still considered new, has only been introduced to them for a few decades while being major brands added products and later refined oil technology.

Awareness about lubricants, and as a result of many people misuse, even sellers and manufacturers misunderstand, making the lubricant industry in the developing countries after decades unable to sublimate. Hence, consumers increasingly dizzy with the matrix of large and small brands.

Number Meaning

First, a quick look at the meaning of SAE viscosity indexes on each can. So what is SAE? SAE stands for Society of Automotive Engineers.

You must have seen the SAE symbol on the oil cans, for example, 5W30, 5W40, 10W40 or 20W50. If 10W40 is taken as an example, the number 10 before W indicates the resistance to freezing of viscous oil at negative temperatures, or the ability to start cold.

It can be easily pumped at temperatures - 30 degrees Celsius and quickly rotate at a temperature of -25 degrees Celsius. In contrast, the number after the W indicates the ability to operate in the positive temperature range. According to the above example, W40 means that the lubricant works well at temperatures below 40 degrees Celsius.

Why Do Car Manufacturers Recommend Using 10W30 Viscosity?

In fact, in recent years, new car manufacturers make this recommendation. But there are still not many lubricant manufacturers designing the W30 series for the tropical market because it is too thin compared to real climate conditions.

10W30 vs 10W40

10W30 vs 10W40 – Differences in Engine Oil Viscosity

In tropical countries, therefore, there is not enough viscosity to ensure optimal engine protection. But why do car manufacturers recommend that consumers use this viscosity? To answer this question, we must learn about machine engineering again.

As you know, to complete a machine part, you need to go through casting, turning, etc. So usually, the newly completed machine parts will still retain a lot of unnecessary details such as metal filings and rough places.

But these extra details, if not abraded, will make the engine not work smoothly. Therefore, when buying a new car, the car company will recommend customers have to go through a running time of the rotor (about the first 1000km), to reduce the excess of the above details.

There is a problem to note here, if high viscosity is used, the lubrication will be more reliable. The thickness will obscure the excess parts making abrasion difficult. Therefore, for the scrape to be active at this time, it needs a little more thinning. It is also the reason why car manufacturers recommend new cars to use W30 viscosity.

Why Should Not Use W30 Viscosity?

As analyzed above, the actual use of W30 viscosity in developing countries is not necessary. During the rotor run, the thickness of W40 is exceptional, but for this abrasion to take place faster, so the car manufacturers recommend using viscosity W30.

But we should note that W30 viscosity in some countries is calculated as thin, even too weak in summer and hot season. Therefore, after the completion of the rotor run time, if we continue to use W30 viscosity, it will lead to the lack of coherence, which causes the metal parts to maintain the collision.

Also, there is a mistake with the car owner. Many people have the idea that they should use the thinning viscosity so that the car will load more and save fuel. But they misunderstood this problem because this concept is only genuine when you are using viscosity too large (more significant than the actual requirements of the car). It would help if you reduced the viscosity to get the effect.

For example, standard viscosity is W40, but if you spend W50, you can reduce it to W40 viscosity so that your car will save more fuel, but if you use too much W30, viscosity, it will be disastrous.

And the danger of this concept is that using too thin viscosity will cause insufficient viscosity to seal the pistons and cylinders and can lead to a loss of power and even more fuel consumption.

Not to mention if using too thin viscosity also reduces the ability to eliminate friction, metal parts rubbing, colliding causing abrasion, engine damage, loud noise, hot engine, etc.

As a lubricant manufacturer with many years of experience in the supply of high-end products, we recommend to consumers - those who have previously held the idea that the more viscous the engine is, the more it will run, before applying, consider the following:

  • Is your car new or used?
  • Is your car long-distance or urban?
  • Is your vehicle in a heavy or light load?
  • Is your car big or small displacement?
  • The actual ambient temperature at operation?

All of these factors influence the decision you need to use.

For example, if you use 10W40 oil to run in the inner city, you will feel the engine is very loading and smooth. But when you switch to run the tour with a long-distance, you may contact the engine starts to heat.

Because when you move to the tour, the engine temperature has increased, the viscous molecules have diluted, and it is the cause of the phenomenon.

Final Verdict

Hopefully, through this article about 10W30 vs 10W40 – differences in engine oil viscosity, you will gain more experience in using lubricants and can choose the type of lubricant that is right for your car without letting the owners of the car repair shop sell it to you.

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