What is wet sump lubrication?

• A. To maintain an oil level on bearings that rotate through oil
• B. To use air lubrication
• C. To operate without any oil in the system
• D. To rely on grease instead of oil

Answer: (A)

Wet sump lubrication is a setup where the oil is stored in a sump (oil pan) at the bottom of the machine, and the level is kept high enough so bearings that rotate are continuously immersed in oil. An oil pump picks oil from the sump and sends it through passages to the moving parts, creating an oil film that reduces wear. The oil then drains back into the sump by gravity, so you have a circulating bath of oil. This approach relies on liquid oil being present in the sump to lubricate those rotating bearings, unlike air lubrication, running without oil, or using grease instead of oil.