A lot of drivers can see 15w-40 or 20W-50 numbers on the outer package of the oil when they choose the oil, and words like API CH-4 API CI-4 can also be seen below. These are the oil grade. What do these labels mean?
SAE 15w-40 what do these mean?
The previous SAE is the abbreviation of the American Association of Automobile Engineers. The viscosity index of the engine oil is formulated by them and is universal all over the world. The latter 15w-40 represents the viscosity index of the engine oil. At the same time, the label also shows that the oil is a multi-grade engine oil, and the current civil engine oil is no longer the same as the previous single-grade engine oil. It means that there is no winter and summer oil, can be used all year round, so let's take 15w-40 as an example to illustrate the meaning.
"W" means that the smaller the number 15 in front of it in winter, the better the low-temperature fluidity of the oil. 15W means that the oil can be used at temperatures above minus 20 degrees Celsius. The latter 40 represents the oil's kinematic viscosity at 100 degrees centigrade ranging from 12.5mm_s to 16.3mm_s, and other viscosity indicators have corresponding standards, not what some people say can be used at 40 degrees centigrade.
What does API CH-4 mean?
API is the abbreviation of the American Petroleum Association. The latter C H-4 represents the grade of engine oil, and the latter C represents the grade of engine oil. S stands for engine oil N, which represents the grade of the engine oil. If marked SN / CF, it is a general purpose engine oil for gasoline and diesel engines.
According to the different letters, you can arrange the rank of the oil, the letters back to indicate the better performance of the oil. And the letters behind the oil to meet the emission standards are even more examples, now the country's five emissions of vehicles, because of the relationship between post-processing, generally need to use CI above the level of oil.
What does ACEA certification mean?
ACEA is the abbreviation of the European Automobile Manufacturing Association, is the European Automobile Manufacturing Industry for automotive lubricants inspection and certification standards, from the technical requirements, higher than the above mentioned American API standards. Many of our major brand oil packaging will see ACEA certification, we can carefully observe the comparison.
ACEA certification of heavy diesel engine lubricants is divided into four grades, they are: E2, E3, E4, E5, E6, E7, E9, the same number is bigger, the higher the grade of the oil, the general brand oil will also certify these corresponding grade standards, you can carefully observe the label on the barrel.
So how do we choose it?
Generally speaking, when choosing the oil, you must first refer to the requirements of the vehicle manual. For example, this car requires 15W-40 CH-4 engine oil. In practice, we can not only select the oil of this grade and viscosity according to the instructions, but also upgrade the grade of engine oil by one grade, that is, we can use CI-4 engine oil of 15W-40 viscosity, and use a higher grade of engine oil to protect the engine better. It can also promote the emission standards.
If your local temperature is below minus 25 degrees Celsius in winter, then we can choose 10w-40 viscosity of oil to make the cold start smoother, but also to ensure that the cold start oil can be pumped to the friction surface. As long as we remember one thing, the last 40 will remain unchanged, and the smaller points in front will have no effect.
If it is an older engine, you can properly choose a slightly higher viscosity of the oil, such as 20W-50 viscosity index, for older engines, the viscosity of the oil slightly better to protect and maintain the normal operation of the engine.
