Abstract: This disclosure provides a method for improving high temperature antifoaming performance of a lubricating oil in an engine or other mechanical component lubricated with the lubricating oil by using as the lubricating oil a formulated oil. The formulated oil has a composition with a lubricating oil base stock as a major component, and at least one silicone antifoaming agent, as a minor component. The silicone antifoaming agent is delivered to the lubricating oil by contacting the lubricating oil with a cured silicone (e.g., room temperature vulcanized (RTV) silicone) at a temperature, and for a period of time, sufficient to deliver silicone to the lubricating oil. The delivered silicone is soluble in the lubricating oil. The lubricating oils are useful as passenger vehicle engine oils (PVEO) and commercial vehicle engine oils (CVEO).