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Question:
How is Oil Weight Measured?
I heard in tech school that the oil weight is measured against kerosene, but a tech told me that it is measured against water. Who is correct?
-- Carol Ingersoll, Beloit, WI
Answer:
The specific gravity of oil is defined as the ratio of the weight of a given volume of the product at 60°F to the weight of an equal volume of water at the same temperature. Water has a density of 8.33 Lbs/Gal at 60°F. So if an oil has a specific gravity of 0.85 then its density is 0.85 (8.33 lbs/gal) = 7.08 lbs/gal. This means if you have 2 gallons of oil then the weight is a little over 14 lbs. As you can see, water is the reference used for these measurements.
