Which characteristic of lubricating oil is crucial for preventing bearing wear?

The thickness of the oil film is crucial for preventing bearing wear because it directly influences how well the oil can separate moving surfaces. A sufficiently thick oil film helps to ensure that metal surfaces do not come into direct contact with each other, which can lead to friction, overheating, and ultimately, wear and tear on the bearings. This hydrodynamic lubrication minimizes metal-to-metal contact, allowing for smooth operation and extending the life of the bearings.

While temperature stability, aroma, and color clarity may be factors to consider in different contexts, they do not play a direct role in lubrication effectiveness or the prevention of bearing wear. Temperature stability is important for maintaining the properties of the oil at varying temperatures, but it does not specifically address how well the oil can form a protective film. Aroma and color clarity have little to no impact on lubrication performance or physical properties related to bearing wear.