When purchasing motor oil, in addition to the viscosity of the oil, we also need to pay attention to the “HTHS” value. Many car owners are most likely to ignore HTHS, or even do not understand what HTHS (High Temperature High Shear Viscosity) is.

HTHS English full name is High Temperature High Shear, Chinese for the oil's “high temperature high shear viscosity”, is the oil in the high temperature high shear viscosity stability indicators, but also reflects the oil in the high temperature high shear conditions of lubrication to maintain the ability. It is also a reflection of the oil's ability to maintain lubrication under high temperature and high shear conditions. It is better and more accurate to understand it as oil film strength.

This parameter is the apparent viscosity, or power viscosity, of the oil obtained by capillary viscosity testing at 150°C. It is tested to simulate the operating temperature and high speed shear conditions of an internal combustion engine cylinder. It is tested under simulated internal combustion engine cylinder operating temperatures and high speed shear conditions, reflecting lubrication between cylinder liner and piston rings as well as the fuel economy of the lubricant.The higher the HTHS value, the lower the oil consumption.

If coupled with high-speed shear movement, when serious boundary friction will occur, if the oil film is not strong enough to rupture, increased wear is inevitable, wear caused by the cylinder inside the sealing is reduced, the oil will run down to the combustion chamber burned.

If you often drive violently or long-distance high revolutions, for example, often driving above 3000 rpm, then you need to increase the requirements for HTHS, and it is recommended to use engine oil with HTHS ≥ 3.5. Turbocharged, large-displacement cars or SUVs, these engines are characterized by fast revolutions and high engine temperatures, and need to be used in conjunction with a fully synthetic engine oil with HTHS ≥ 3.5 and high viscosity index.

Now there are many German models of the engine oil burning phenomenon, which is directly related to the use of engine oil HTHS. Because HTHS is used to describe the friction vice, piston ring and cylinder wall friction at the state of the oil, burning oil is because HTHS is low, of course, to exclude because of the valve oil seal and other problems caused by burning oil, then you should go to choose HTHS higher oil.