Oil viscosity classification is performed by which organization?

• A. Society of Automotive Engineers
• B. American Petroleum Institute
• C. British Standards Institution
• D. Institute of Electrical and Electronics Engineers

Answer: (A)

Viscosity classification for engine oils is defined by SAE International. They publish the J300 standard that specifies the SAE viscosity grades (such as 0W, 5W, 10W for cold-start behavior and 20, 30, 40 for hot viscosity at 100°C). This system tells you how thick the oil is when cold and when the engine is hot, guiding proper lubrication and protection. The other organizations listed don’t set the viscosity grade: API handles performance categories and service requirements, while BSI and IEEE aren’t responsible for automotive oil viscosity classifications.