Is it necessary to have expensive oil? 1 minute teaches you to understand "oil specifications"

How to choose a can of oil suitable for your car? Instead of listening to the story, it is better to know the label attached to the oil bottle.

There are kinds of oil

The oil itself is composed of “base oil” plus “additives”. There are currently three common base oils on the market: “mineral oil”, “semi-synthetic oil” and “synthetic oil”.

Mineral oil is the lowest cost base oil. It is composed of hydrocarbons. It has poor fluidity, high volatility, temperature resistance, low viscosity and low viscosity index at low temperatures.

Although mineral oil has many shortcomings, price is its biggest advantage.

Synthetic oil is a base oil composed of ethylene and propylene in crude oil, which is then synthesized into a large molecule by a complicated chemical reaction such as polymerization and catalysis.

Compared with mineral oil, synthetic oil has better low-temperature fluidity, and has better performance in oxidation resistance, low volatility and corrosion resistance. But relatively speaking, synthetic oil prices are also higher.

Semi-synthetic oil is a product purified by hydrocracking technology on the basis of mineral oil. It is a mixture of mineral oil and fully synthetic motor oil in a certain proportion. The purity of semi-synthetic oil is very close to that of synthetic oil, but Its cost is slightly higher than mineral oil; it is an ideal transition product for mineral oil to synthetic oil.

Oil viscosity selection

The oil viscosity has a very strong relationship with the working environment of the engine. Too thick or too thin is not a good condition. For example, in the ice and snow, the viscosity of the oil is too high, which will cause no ** to flow to the parts for lubrication. In severe cases, the engine will not start normally.

In hot areas, if the viscosity of the oil is too low, it may become thinner after being heated, resulting in no lubrication, resulting in wear and tear of parts.

The marking of the oil viscosity is currently based on the SAE J300 developed by the Society of Automotive Engineers (SAE).

The viscosity grade ranges from 0 to 60. The higher the number, the higher the viscosity, and the 0-25 is followed by a letter W, which stands for Winter (winter), indicating its viscosity when the cold car starts at low temperature.

Most of the oils currently used in motor vehicles are multi-grade engine oils, that is, in different environments, they do not have a viscosity grade.

Take the oil labeled "0W-30" as an example. "0W" means that the oil can still work normally at a temperature of minus 35 degrees, and 30 is a viscosity level of 30 when it is 100 degrees.

Oil certification standard

The standard of motor oil needs to be certified by a third-party agency. This regulation not only further verifies the quality of the oil, but also makes consumers feel more at ease in purchasing!

Currently, the market mainly uses the American Petroleum Institute (API) as the standard. The engine oil grade of a gasoline engine is generally composed of two letters, and the lowest is SA and the highest SN. The letters behind are large, indicating the higher the oil level.

Mineral oils are generally of the SJ grade, semi-synthetic oils are generally SJ to SM grade, and fully synthetic oils are grades above SM.

Oil does not need to pursue high prices

"I can't remember all of this information. What should I do when I choose oil?" The most convenient way is to follow the advice on the vehicle's instructions.

Under the same viscosity grade, the higher the quality grade, the more expensive the oil, so "all synthetic motor oil" is much more expensive than "mineral oil".

Many car owners will think that the quality of high-priced oil is better, and the protection of cars is better. The cheap "mineral oil" will hurt the car. This view is not accurate.

As long as the viscosity grade and quality grade of the oil product meet the manufacturer's recommended level and the vehicle maintenance is carried out according to the manufacturer's recommended maintenance cycle, we can safely use the affordable "mineral oil".