carEngine oil has the functions of cooling, lubricating, cleaning and sealing, which plays a vital role in ensuring the normal operation of the engine, and directly affects the comfort of the vehicle, the level of exhaust emissions and the life of the engine. Therefore, it is very necessary to master the relevant oil knowledge.
First of all, the state of the oil is directly related to the working temperature of the car. The viscosity of the oil at different temperatures is different, and its lubrication and sealing effects are also different. If the engine load is large,Rotating speedWhen it is low or severely worn, oil with a higher viscosity should be used. The indicator that reflects the viscosity is the SAE standard, that is, the viscosity index of the engine oil. SAE standards are usually expressed as 0W-30 and 10W-50. The letter W indicates that the product is a multi-grade engine oil, which is applicable to a large temperature range, and its viscosity can be adjusted within a certain range. The number in front of W represents the viscosity of the oil at low temperatures, and the number at the back represents the viscosity of the oil at high temperatures, that is, the performance of the oil's lubricating ability at high temperatures.
Generally speaking, in winter, if a higher viscosity oil is used, it will startmotor、Batteries, etc. increase additional losses, and at the same time increase fuel consumption due to increased internal resistance. In summer, the use of engine oil with insufficient high-temperature performance will make it difficult to form a sufficient protective film during the working process of the engine, which will cause insufficient lubrication and cause wear of the parts.
In addition, different driving habits require different oils. If you are a driver who often likes to shift gears at high speeds, long-term high-speed operation will cause the engine's operating temperature to remain high. This type of car owner is best to choose a more heat-resistant engine oil, such as SAE15W-50, SAE10W-40, etc. Achieve better heat dissipation effect. If the temperature is very low at the moment, considering the starting performance, a motor oil with a large temperature span, such as SAE0W-40, is the best choice.
The quality of engine oil is marked by API quality. API quality is divided into gasoline and diesel. The gasoline engine oil is mostly above the SG grade. The API quality of diesel engine oil is divided into 7 grades from CA to CG. Generally speaking, most of the oil products that can meet high-grade and stringent standards are synthetic and semi-synthetic oils. Fully synthetic oil has a higher viscosity index than ordinary mineral oil, and its service life is also longer. However, fully synthetic engine oil has excellent permeability in high-temperature working environment, and it is not suitable for old cars and low-end cars.
The oil replacement cycle is stated in the maintenance manual of most models as every 5,000 kilometers or 7,500 kilometers. With the continuous improvement of engine structure, the period of regular maintenance and oil change is getting longer and longer, and many models can be extended to more than 10,000 kilometers. However, if you often drive in the city, and most of the distance per trip is less than 10 kilometers, in this kind of exhausting driving situation, it is recommended to shorten the interval between oil changes to effectively protect the engine.
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