Coast Guard Exams
Question 42General Subjects - QMED70% to pass

If an engine lubricating oils viscosity is given as SAE 20W as compared to SAE 20, what is the significant difference between the two lubricating oils?

AI Explanation
The correct answer is B. The "W" in SAE 20W indicates that the oil is designed for winter or cold weather operation, meaning it has better low-temperature fluidity compared to the SAE 20 oil. The SAE 20W oil is primarily intended for low ambient temperature service, while the SAE 20 oil is primarily intended for high ambient temperature service. The other options are incorrect because they either incorrectly characterize the differences between the two oils or do not accurately reflect the intended operating temperatures for each type of lubricating oil.