The most crucial component for any vehicle to run seamlessly on the road is the engine (motor) oil. Engine oil is the lifeblood of any car’s engine.
Functions of Engine Oil
• Lubricates various internal components of the engine, prevents friction between them, and reduces their wear and tear
• Helps to prevent rust and corrosion
• Acts as a coolant and absorbs heat, thereby preventing overheating
• Cleans engine by removing sludge and soot from the engine block
• Neutralizes the acids released during the combustion process
Considering the wide range of functions performed by the engine oil, it is clear that it is an essential element of our vehicle’s engine.
Did you know that not all engines can use the same engine oil? Different engines need different engine oils in order to function optimally. In order to deliver top-notch performance and increase the longevity of your vehicle, it is important for you to select the motor oil that has the appropriate grade of oil viscosity. There is a wide range of motor oil viscosity grades available in the market and you need to choose one the proper one for your engine.
What are Motor Oil Viscosity Grades?
• The viscosity of engine oil is measured by its resistance to flow or how easily it flows at a specified temperature.
• The Society of Automotive Engineers (SAE) has established a unique coding system to grade motor oils.
• Engine oils are categorized into different grades on the basis of the oil viscosity.
• Different engine oils behave differently during changes in temperature.
• The choice of the ideal viscosity of engine oil depends on your engine and the climate in which you are driving.
Measuring Viscosity of Engine Oil
The motor oil viscosity grades consist of four characters XW-XX. The first two numbers, i.e. one preceding the letter W and the other succeeding the letter W determine the oil viscosity.
• The letter ‘W’ stands for winter, while the number that comes before W indicates how the engine oil will react in cold conditions (cold engine start). The lower number before ‘W’ means less thickening and better flow in cold conditions. For example, the 5W-30 grade will have a better flow than 10W-30 grade in cold conditions.
• The second number after the letter ‘W’ is an indication of how the oil flows at higher temperatures (normal engine operating temperatures). The lower number after ‘W’ means less thickening and easier flow at higher temperatures. For example, the 5W-30 grade will have a better flow than the 5W-40 grade at normal engine operating temperatures.
Motor Oil Viscosity Testing Steps
Engine oil viscosity can be tested as follows:
• Fixed volume of an engine oil sample is introduced into the viscometer tube.
• The sample flows through the tube.
• The time required for the sample to flow through the calibrated portion of the tube is recorded.
• The recorded time is multiplied by the tube’s calibration factor to give the oil viscosity in centistokes (cSt).