During which phase is the pre-lubrication pump activated?

During which phase is the pre-lubrication pump activated?

• A. During shutdown
• B. During idle
• C. During startup
• D. During full load

Answer: (C)

Pre-lubrication is used to prime the oil system before the engine turns over, ensuring bearings and moving parts are already lubricated the instant the engine starts. Activating the pre-lubrication pump during startup pushes oil through the galleries and into critical bearings so oil pressure can come up quickly when the crank begins to move. This minimizes dry starts and reduces wear on startup. After a brief priming period, the normal lubrication pump takes over once adequate pressure is established. It’s not employed during shutdown, idle, or full-load operation, because those phases rely on the regular pump to maintain lubrication rather than prior priming.

Pre-lubrication is used to prime the oil system before the engine turns over, ensuring bearings and moving parts are already lubricated the instant the engine starts. Activating the pre-lubrication pump during startup pushes oil through the galleries and into critical bearings so oil pressure can come up quickly when the crank begins to move. This minimizes dry starts and reduces wear on startup. After a brief priming period, the normal lubrication pump takes over once adequate pressure is established. It’s not employed during shutdown, idle, or full-load operation, because those phases rely on the regular pump to maintain lubrication rather than prior priming.