How to distinguish the quality grade of engine lubricant?

1. Diesel engine oil.

There are two main bases for the selection of diesel engine lubricant quality grades. First, according to the sum of the mechanical load and thermal load of the automobile engine, it is expressed by the strengthening coefficient; Then it depends on the harshness of the engine operating conditions.

2. Gasoline engine oil.

According to the harshness of the engine working conditions and the additional devices in the intake and exhaust system of imported automobiles and the production age, the gasoline engine oil with the corresponding performance level (quality grade) is selected. Generally speaking, high quality grades can replace low quality grade oils, but you should never replace high quality grades of oil with low quality grades, otherwise it will lead to engine failure or even damage.

It should be said that the above grades are applicable to diesel engines, the further back the letter after C, it means that the higher the quality grade of the oil, the more suitable it is for high-strengthening diesel engines, like general non-supercharged diesel engines, CD grade oil can, but if you use CF, CH and other levels of oil, it is only good for diesel engines, and there is no harm. Using good engine oil can extend the oil change time appropriately. In general, the quality grade of the engine oil required for the supercharged diesel engine is higher, for example, the non-supercharged diesel engine uses CF grade oil, and the same type of supercharger needs to use CH grade oil.

CH-4 means that the oil is suitable for 4-stroke diesel engines, and if it is a two-stroke diesel engine, it needs to be used with caution.

For the international recognition of lubricating oil viscosity and quality level, SAE's oil viscosity classification method and API quality grade standard are adopted. The Yuantian No. 1 series produced by Beijing Runhua Yuantian Biotechnology Co., Ltd. has passed the American Petroleum Institute (API) quality certification in December 2015.

How to classify engine oil and how to choose the viscosity of engine oil? Yacco French imported lubricating oil to tell you below: in fact, the bottle will have the viscosity of organic oil, and it is generally in a conspicuous position, you can see at a glance, the viscosity of the engine oil is very simple, such as:

SAE 5W 30, some bottles will be marked with SAE, while others will be marked directly with viscosity. (as shown below).

What is motor oil viscosity?

SAE (Society of Automotive Engineers) refers to the American Society of Automotive Engineers, and the viscosity standard for motor oil formulated by it is used worldwide. The viscosity of engine oil is the most important characteristic of engine oil, which is simply the resistance of fluid flow, and the so-called viscosity and thinness of oil refer to the size of viscosity.

Oil viscosity grading.

SAE uses a viscosity classification system that classifies motor oils into high-temperature types for summer, low-temperature types for winter, and all-weather types for winter and summer. There are 6 kinds of winter oils, 4 kinds of summer oils, and 16 kinds of winter and summer general oils.

1.Winter oil.

0w, 5w, 10w, 15w, 20w, 25w, the symbol "w" represents winter, the smaller the number in front of "w", the smaller its low temperature viscosity, the better the low temperature fluidity, and the lower the applicable minimum temperature.

2.Summer oil.

20, 30, 40, 50, the higher the number, the greater its viscosity, and the higher the applicable maximum temperature.

3.Winter and summer all-purpose oil.

5W 20, 5W 30, 5W 40, 5W 50, 10W 20, 10W 30, 10W 40, 10W 50, 15W 20, 15W 30, 15W 40, 15W 50, 20W 20, 20W 30, 20W 40, 20W 50, the smaller the number representing the winter part, the larger the number representing the summer part, and the wider the temperature range it is applicable to.

Engine oil viscosity requirements.

Good low-temperature start-up: the viscosity should be small at low temperature, and the low-temperature fluidity of the oil product is good, so that the oil can flow quickly to each machine part to exert lubrication and protection performance. Most of the engine wear is caused during starting, especially the wear caused by cold starting, and only a small part of the wear is caused during operation.

The higher the viscosity, the stronger the oil film is usually stronger, the greater the viscosity, the thicker the oil film attached to the metal surface, and the oil film must be thick enough to exert lubrication and protection properties. However, the viscosity of the oil changes with temperature:

When the temperature rises, the viscosity decreases (thinning), and when the temperature drops, the viscosity increases (thickens).

Therefore, the ideal oil is a suitable choice made by having high fluidity with small viscosity at low temperature and stability with high viscosity at high temperature, combined with specific driving road conditions, engine load levels and air temperature.

In the motor oil industry, it is divided by quality grade and viscosity grade, and the quality grade adopts the grade classification standard formulated by API. Viscosity grades are based on the grades established by SAE.

Mass division: s"The opening series represents gasoline engine oils"c"The opening series represents diesel engine oils! From "SA" all the way up to "SL", with each letter, the oil will perform better than the previous one, and there will be more additives in the oil to protect the engine. The lower the letter, the higher the quality grade, and most of the oil grades in international brands are above the SF grade.

When S and C exist at the same time, it means that the two can be used at the same time, in gasoline engine oil, the quality grade starts from A and ends with N, the lower the letter, the better the quality and quality of the engine oil, and the international brand of engine oil is mostly above the SF level.

Viscosity classification: According to the standard 10W-40, the number before W represents the fluidity of the oil at low temperatures, and the lower the value, the better the start-up performance. The number after W represents the stability of the oil at high temperatures, sorted from 0W to 25W, the higher the value, the better the stability of the oil at high temperatures. The larger the value, the better the engine protection, more suitable for the old car.

The advantage of a smaller value is that it saves fuel and is less noisy. Suitable for new cars or naturally aspirated engines.