Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/1275515
2 | July - August 2020 | www . machinerylubrication.com Insp e c tion AS I SEE IT Jim Fitch | Noria Corporation The Most Important Lubrication Inspection Abnormal Changes in Oil Level A sudden change in oil level, either up or down, is a tele- graphed alert that something is wrong. And, this "something" could potentially be serious. Deferring maintenance or ignoring this alert could lead to a costly repair and longer downtime in the future. e frequent exam- ination of quality oil level sight glasses by trained inspectors is a sound condition monitoring prac- tice. Perhaps the most important of all lubrication-related inspections. Whether oil goes up or down, any sudden change in the oil level requires troubleshooting in search of the cause and corrective action. Just adding more oil or removing excessive oil is an activity of treating the symptom, not the cause. True, some oil level changes are rather common and quickly understood. For instance, if oil goes sharply down, you might have a conspic- uous leak (internal or external) that can be easily found and plugged. Internal leakage occurs when a fluid has gone from one compart- ment to another. Leakage may be associated with seal failure or perhaps the wrong oil in use. Low viscosity oils leak faster than high viscosity oils. An abrupt chemical change in a lubricant can affects its interfacial tension which can increase the rate of leakage. If the oil level goes up, this may be due to the introduction of new fluid. For example, perhaps someone added too much oil, or another fluid like a coolant or even fuel has entered the system, which has raised the oil level. What do Changes in Oil Level Mean? Oil Too High: When oil levels rise above the acceptable range usually something new has been added, i.e., a new fluid. But there are other options too. • Too much makeup f luid. Adding makeup fluid without carefully watching sight glasses can cause over-lubrication. • Oil drain back. If f luid is topped off while the machine is running, the oil level can climb when it stops and oil drains back from gears, bearings, oil galleries and distant zones or oil ways. • Aeration and foam. Such conditions can double or triple the apparent oil level. "Whether oil goes up or down, any sudden change in the oil level requires troubleshooting."