If the oil pressure gauge on a gasoline engine drops to zero, what should be done first?

When the oil pressure gauge on a gasoline engine drops to zero, the first necessary action is to stop the engine. This is important because a zero oil pressure reading indicates that there is insufficient oil circulating through the engine, which could lead to serious engine damage due to lack of lubrication. Running the engine under these conditions can result in overheating, increased wear, and ultimately, engine failure.

Stopping the engine immediately prevents further damage and allows for a safe assessment of the issue. Once the engine is off, the next steps would involve inspecting the engine and determining the cause of the low oil pressure, such as checking oil levels, potential leaks, or mechanical failures. Addressing the problem while the engine is still running could lead to catastrophic damage, emphasizing the critical nature of the initial response in this situation.