The advantages of using detergent additives in highly stressed internal combustion engines are now taken for granted, but there is still room for improved additives. It is not yet possible to extend the periods between oil changes merely by changing to a Heavy Duty Oil, because the additive becomes depleted by virtue of the fact that it has done its job. The more highly stressed the engine, the more quickly will the additive be used up, particularly if the engine is of the type that is prone to form more engine deposits.
Industrial Lubrication and Tribology – Emerald Publishing
Published: Feb 1, 1951