Which of the following engine servicing operations generally requires engine pre-oiling prior to starting the engine?

Pre-oiling an engine is a critical step in certain servicing operations to ensure that the engine is adequately lubricated before it starts, particularly after components that affect the oiling system have been serviced or replaced. When an engine is installed, there is often significant disruption to the oiling system, including disconnection of oil lines and the potential for air to be trapped in the oil passages. Pre-oiling helps to circulate oil before startup, preventing metal-to-metal contact in areas that may not be adequately lubricated immediately upon starting the engine. This practice is essential to prevent damage to engine components due to lack of lubrication.

In contrast, during an engine oil and filter change, the system typically retains some oil, and the filter change doesn't usually require a complete pre-oiling process. Similarly, while replacement of oil lines might potentially require consideration of oil flow restoration, it does not always necessitate pre-oiling if one manages to maintain oil presence during the replacement. Routine maintenance checks do not usually involve such drastic changes to the oiling system where pre-oiling would be a requirement. Therefore, engine installation is identified as the operation most commonly necessitating engine pre-oiling prior to starting.