Final answer:
Engine lubrication issues can be identified by a dashboard warning light, unusual noises, and excessive exhaust smoke. Correct oil viscosity is essential for proper engine protection at all temperatures.
Step-by-step explanation:
Indicators that signal when an engine is not properly lubricated include the illumination of the oil pressure warning light on the dashboard, unusual engine noises, and excessive exhaust smoke. Engine lubrication is critical for preventing damage and ensuring efficient operation. Inadequate lubrication can lead to increased friction and wear on engine components such as valves, pistons, bearings, and can result in serious issues like engine knocking or pinging. It's important to use oil with the correct viscosity, which refers to the oil’s thickness or flow characteristics. The right viscosity ensures the oil remains effective at both low and high temperatures, maintaining a protective barrier between moving parts.