How are drain and vent lines used in the lubrication circuit and what issues indicate blockage?

• A. Drains carry oil away from bearings; vents allow air to escape; blockage causes oil pooling, overpressure, leaks, or poor scavenge.
• B. Drains are for fuel; vents are for coolant.
• C. Drains remove water only; vents remove air.
• D. Drains and vents are unnecessary.

Answer: (A)