In a dry-sump lubrication system, what is the role of the external reservoir?

• A. Cools the oil directly
• B. Stores oil and allows scavenger pumps to return oil
• C. Provides air for venting
• D. Houses the main pump

Answer: (B)

In a dry-sump system, oil is stored in an external tank rather than in the crankcase. The reservoir’s job is to store that oil and provide a return path for the scavenger pumps that pull oil from the crankcase and push it into the tank. This keeps the crankcase relatively oil-free, reduces windage, and ensures a consistent oil supply even during high-G or inverted operation. The pressure pump then draws oil from the reservoir to lubricate bearings and gears, maintaining steady pressure. The reservoir also helps with air/oil separation, but cooling is handled by a separate oil cooler, and the main pump is driven independently and draws from the reservoir rather than occupying it as the primary purpose.