Low foaming railway diesel engine lubricating oil compositions

摘要

A low foaming lubricating oil composition comprising a mineral oil, an oil soluble detergent-like additive which increases the foaming tendency of the lubricating oil, and an effective amount of an estolide of a hydroxy fatty acid having 10 to 24 carbon atoms which reduces the foaming tendency of the lubricating oil composition. The lubricating oil achieves the low foaming tendency without added silicone polymers and has a silicon content of less than about 10 parts per million by weight. The preferred estolide is the estolide of 12-hydroxystearic acid.