Abstract: A system for measuring the quality and level of lubricant in an engine lubricant reservoir includes a valve for selectively directing a portion of lubricant from the engine through a first conduit for return to the engine or through a second conduit for removal from the engine. Within the first conduit are one or more sensors for sensing the condition of the lubricant passing through the first conduit. The sensors are monitored by a controller which is operative selectively to cause the valve to block the flow of lubricant through the first conduit and direct a portion of the lubricant through the second conduit based on the monitored conditions of the lubricant. Also, the controller directs a supply of fresh lubricant to the engine in response to the lubricant in the engine lubricant reservoir dropping below a predetermined level.