The choice of engine oil is to determine the viscosity first, and then choose the appropriate brand.
However, the viscosity has a fixed standard, and the grade can be freely selected, so it is better to look at the grade first: the choice of engine oil grade is based on the comprehensive judgment of vehicle grade, engine type and mileage, and only the lowest grade mineral engine oil can be used, or the low-end synthetic engine oil can be used to extend the replacement mileage.
There are three grades of engine oil: mineral engine oil, semi-synthetic engine oil engine oil and all-synthetic engine oil engine oil. The applicable models and mileage of the three grades are roughly as follows:
1, mineral engine oil is suitable for ordinary small-displacement naturally aspirated engines, which have low operating temperature and low requirements for thermal decay ability of engine oil; The B 12-LSI general-purpose engine used in Guang Zhi belongs to the standard entry-level power, and high-end engine oil is not needed.
2. Semi-synthetic engine oil is blended with mineral base oil and synthetic engine oil in the ratio of 40:60, and the addition of synthetic engine oil prolongs the thermal decay rate of engine oil to a certain extent; In theory, it is no problem to use 1000 km for LSI-class engines, but it is generally recommended to replace it at 7500 km in the industry, but the price of this kind of engine oil is slightly higher, which is not cost-effective.
Synthetic engine oil is artificially synthesized by chemical means. Its principle is different from the basic lubricating oil extracted from crude oil. It is very resistant to thermal decay, and the LSI engine can be used normally for 10 thousand kilometers. However, in synthetic engine oil, the price is very high, which is basically 3~4 times that of mineral engine oil. However, there are some small brands of synthetic engine oil whose prices are slightly lower, but whether the quality can reach the ultra-high performance of synthetic engine oil has not been tested.
Therefore, Wuling Light still suggests using ordinary mineral engine oil and replacing it every 5,000 kilometers. It is reasonable to control the treatment of engine oil, mechanical filter and air filter between 120~ 150 yuan. The performance-price ratio of using this oil is higher than that of low-end synthetic oil. As for the choice of high and low temperature viscosity of engine oil, it is relatively simple to determine the low temperature fluidity first.
The recommended engine oil standard should be a W-30, where W refers to the low-temperature fluidity in winter, and this value should be determined according to the actual ambient temperature of the place. Add -35 to the number before w to get the freezing point of engine oil:
0+(-35)=-35 degrees Celsius
5+(-35)=-30 degrees Celsius
Analogy in turn
The freezing point temperature is suggested to be 5~ 10 degrees higher than the actual minimum temperature. There is a certain redundancy to ensure that the oil can flow effectively at the moment of cold start, forming pressure lubrication and splash lubrication, and the engine can effectively reduce wear and prolong service life.
It is recommended to use 30-grade high-temperature viscosity, and do not replace it easily. After the engine reaches the ideal working temperature, if the viscosity is appropriate, the power and fuel consumption are normal. If the viscosity is reduced from 30 to 20, the power will be improved, but the viscosity is small and the fluidity is high, and the oil film in the splash lubrication part will be quickly lost, resulting in a lot of poor quality and accelerating the wear of the engine; If the viscosity increases when upgrading from 30 to 40, the running resistance of crankshaft increases synchronously, the fuel consumption increases and the power decreases.
Therefore, it is only suggested that the viscosity cannot be changed easily, and the viscosity can only be upgraded by one level after the mileage is enough and the engine starts to burn oil slightly. The purpose is to increase the thickness of oil film to fill the gap between piston and cylinder wall, so as to reduce oil loss.
The choice of engine oil can refer to this standard, and the highest cost performance of Wuling Light is to use the lowest grade;