Understanding the Motor Oil Viscosity Classification System

Maxmo Lubricants has always recognized the critical importance of viscosity in motor oil performance, aligning seamlessly with the development of motor oil classification. The earliest pursuits to categorize motor oils, significantly influenced by the introduction of automobiles, emphasized viscosity as a primary attribute. This acknowledgment led to the collaboration between the Society of Automotive Engineers (SAE) and engine manufacturers, culminating in a viscosity-based classification system.  

Maxmo, with its foundation imprinted in the advancement of automotive lubrication, leverages this classification to engineer products that excel in both cold and high operating temperatures, reflecting a profound understanding of viscosity’s role in engine longevity and efficiency. 

The Essential Guide to Motor Oil Viscosity Classification System and Your Vehicle

Understanding the viscosity of motor oil is essential for ensuring efficient engine operation in both cold and high temperatures. Viscosity, primarily the thickness or fluidity of the oil, affects its movement through an engine, providing lubrication, reducing friction, and ensuring smooth engine operation. In colder temperatures, oils need to be fluid enough to circulate quickly, while in higher temperatures, they should not become too thin to maintain proper lubrication. 

At Maxmo, we recognize that the viscosity of motor oil at colder temperatures is just as crucial as its performance at high operating temperatures for the long-term health of an engine. By leveraging advanced cold cranking simulators and adhering to centipoise (cP) and Centistoke (cSt) measurements, we ensure our lubricants offer unmatched protection and efficiency, representing our value of customer satisfaction through product reliability.

Clarifying SAE J300 Viscosity Grades for Motor Oil 

Check the chart below which is divided into two sections, showing the SAE J300 standards for motor oil viscosity grades. These will help the users select the appropriate motor oil. 

The first section, labeled “SAE J300 winter grades,” details the grades assigned to motor oils for cold-weather performance. Each grade is associated with a specific low-temperature viscosity measured in centipoises (cP) using a Cold Cranking Simulator (CCS), and a pumping viscosity also in cP. These values ensure that the oil maintains good flow and pumpability in cold conditions. The kinematic viscosity, measured in centistokes (cSt) at 100°C, is also listed for each grade, indicating the oil’s resistance to flow at engine operating temperatures. 

The second section, “SAE J300 non-winter grades,” lists the kinematic viscosity grades for motor oils at operating temperature (100°C). This section includes the minimum and maximum kinematic viscosity values for each grade and the High-Temperature High Shear (HTHS) viscosity measured in cP at 150°C. HTHS viscosity is important because it reflects the oil’s ability to maintain a film and protect engine parts under high temperatures and shear conditions. 

SAE J300 winter grades  

SAE J300 non-winter grades