Jeppesen Powerplant Orals Practice Test

Excessive oil consumption in a reciprocating engine without visible oil leaks is often attributed to worn or broken piston rings. The piston rings play a critical role in maintaining the seal between the combustion chamber and the crankcase. When these rings become worn or damaged, they can no longer effectively seal the combustion chamber. This results in oil being drawn into the combustion area and burned during the combustion process, leading to noticeable oil consumption without any external leaks.

In contrast, while a faulty oil pump could potentially affect oil pressure and circulation, it typically wouldn't directly cause excessive oil consumption. Similarly, a clogged oil filter primarily impacts oil flow and can lead to engine problems but does not directly correlate with oil being consumed or burned. Lastly, a low oil level is a symptom of oil consumption rather than a cause; it indicates that oil is already being consumed excessively or not being replenished adequately.

Thus, the correct answer emphasizes the mechanical factor within the engine that directly leads to increased oil usage during operation.