Separation of Oil in Lubricating Greases

Oil separation is a natural phenomenon in lubricating greases. This process can be observed as oil accumulating at the top of drums or cartridges when they are stored, or as occasional drips if the grease is in use in items such as bearings. This is not a matter of grease quality; it is a characteristic that depends on the type and quantity of thickener, which accelerates with temperature and can be modified according to the requirements of the application.

In the case of oil tanks found in stored drums with a greater quantity of oil separated over time, it is possible and recommended to incorporate the separated oil again using mechanical means.

The following video demonstrates the safe and effective implementation of this method.

Furthermore, oil separation is a characteristic that we measure at FUCHS and can be found in most of our data sheets. This value is expressed as a separate weight percentage. Common measurement periods include 18 hours and/or 7 days at 40°C. However, these values can be adapted as required. This is an important measurement because a value outside the stipulated range could lead to a change in the consistency of the grease, potentially leading to an undesired alteration in lubrication. 

The following video provides an overview of the fundamental principles involved in this measurement.