What is the viscosity of motor oil, and how does it affect engine performance

The main task of engine oil is to ensure minimum friction of the moving parts of the engine. Since the motors of cars operate over a very wide range of temperatures, it is not possible to create a lubricant that would ensure an optimum operating mode under any operating conditions. Because the engine manufacturers Determine the most suitable brands of oils, which provide the maximum possible efficiency with the minimum possible wear of parts under certain operating conditions of the motor. There is a division of lubricants into "summer" and "winter", which differ primarily viscosity.

To put it simply, the viscosity of the engine oil characterizes its ability to remain on the surface of the part while maintaining fluidity. This quantity is variable and depends on temperature. Properly selected viscosity of the engine oil can prolong the life of the motor. Incorrect selection of the lubricant leads to premature engine wear. In order for it to be somehow Oriented in the range of lubricants, a classification was developed. According to the Russian GOST all they are divided into:

• Winter;
• Summer;
• All-weather.

For all grades, the kinematic viscosity at a temperature of 100 ° C is determined, and for all-weather and winter even at -18 ° C. In most countries, the SAE classification developed by the American Society of Auto Engineers has been adopted.

It is believed that the higher the high-temperature viscosity of motor oil, the better. This is not true. And though for sports cars it is recommended to apply a high viscosity index of motor oil, this does not mean that, in the bay in your engine, a viscous lubricant, you will make from a standard sports car a supercar. The motor will not work better. There will be all the opposite: the engine will quickly lose power and will require major repairs, and even replacements.

The service book lists the viscosity of the engine oil most suitable for your engine. In determining this parameter, manufacturers took into account all possible modes of operation of the motor and all its speed modes. Therefore, the most optimal viscosity parameters are indicated there.

The use of oils with an overestimate or underestimated viscosity index is detrimental to the motor. At low viscosity, the motor can jam, and at a high index it constantly works at elevated temperatures (due to increased friction), which accelerates wear. In addition, high temperatures contribute to the rapid oxidation of oil, and therefore, it needs to be changed more often. The use of a high viscosity lubricant will not affect the operation of the motor as soon as possible. But what will happen is absolutely certain. Therefore, at STO, ask to fill in oil according to the manufacturer's recommendations, regardless of what the workers say to you: it is advantageous for them to repair their car as often as possible after the warranty period. Take care of your car yourself.

Modern brands of motor oils retain operational properties for 500-2000 hours of engine operation, which is 12-45 thousand kilometers. Replacement of the lubricant should take place simultaneously with the change of filters and maintenance of the car. In this case, a long-term high-quality engine operation will be provided (provided that the manufacturer's recommended brand is used).