Which property of engine oil is crucial for providing protection at high temperatures?

Viscosity is the property of engine oil that is crucial for providing protection at high temperatures. It refers to the oil's thickness and its ability to flow at various temperatures. As engine oil is heated, its viscosity can change, impacting its lubricating capabilities.

At high temperatures, oil must maintain an appropriate viscosity to effectively reduce friction between moving engine components. If the oil becomes too thin due to high temperatures, it may not provide adequate protection, leading to increased wear and tear. Conversely, if the oil is too thick at lower temperatures, it may not flow properly to provide necessary lubrication.

The other properties mentioned do not directly address the ability of oil to protect against the heat generated within an engine. Pour point refers to the lowest temperature at which oil will flow, which is more relevant for cold start performance rather than high-temperature operation. Color is not a functional characteristic that impacts the oil's performance; it varies due to the base stock or additives used. Flash point indicates the temperature at which oil can ignite, but it does not directly correlate to its protective capabilities in high-temperature scenarios.