What is the function of a constant level oiler?

• A. To use gravity to feed more oil as needed to make up for any leakage
• B. To maintain a constant oil pressure regardless of level
• C. To remove excess oil from the sump
• D. To circulate oil only during startup

Answer: (A)

Constant level oilers keep the lubrication system at a steady oil depth by feeding oil by gravity from a reservoir. As oil leaks away or is drawn off, the level in the sump drops, and the oiler’s float or valve opens to let more oil flow in until the preset level is restored. This ensures a continuous, gravity-fed supply to the bearings, even as losses occur. It’s not about keeping oil pressure constant, removing excess oil, or circulating oil only at startup.