Circulating oil systems are used when expected bearing operating temperatures are too high for most lubricants. A lubrication system provides auxiliary cooling and storage capacity that can make a positive difference in bearing operation. Lubrication units are also good choices when there is no cooling water available for sleeve bearings. Most lubrication sets use pressurized oil feed and gravity return. They also feature instrumentation that can advise when the oil temperature is too high or flow is interrupted.