Definition: Refers to the ability of grease to resist being washed out of ball bearings by water under test conditions. This is a critical factor when selecting grease for machinery operating in humid environments.

① Under specific conditions, the percentage mass of grease washed away by water is measured. The smaller the loss, the less the performance changes upon water exposure. Such grease exhibits better water resistance, making it more effective for sealing and protective applications. This is one of the most important indicators of grease’s sealing and protective properties.

? Test Standard: SH/T 0109 “Test Method for Water Washout Resistance of Grease”, Equivalent Method: ASTM-D1264