What could be a result of an engine operating with degraded oil?

Operating an engine with degraded oil can lead to increased wear on moving parts. Engine oil serves several critical functions, including reducing friction between moving components, dissipating heat, and preventing corrosion. When oil degrades, its ability to lubricate properly diminishes, which increases the friction and wear on parts such as bearings, pistons, and camshafts. Over time, this excessive wear can lead to engine failures, reduced efficiency, and ultimately, a need for more extensive repairs or replacements.

In contrast, improved fuel efficiency, enhanced power output, and no change in performance are unlikely scenarios when oil quality is compromised. Degraded oil typically fails to maintain the necessary lubrication, which can lead to a decrease in engine performance and efficiency rather than an improvement.