Abstract: An enhanced system for monitoring clogging of a fluid filter. A differential pressure sensor connects to fluid lines on opposite sides of the filter to measure a pressure difference across the filter. A viscosity-indicating property sensor connects to one of the fluid lines to measure a viscosity-indicating property of the fluid. A filter monitor in communication with the differential pressure sensor and the viscosity-indicating property sensor issues an operator alert when the pressure difference across the filter exceeds a differential pressure set point. The differential pressure set point is a function of the viscosity-indicating property of the fluid in the fluid line. In one embodiment, a fluid flow rate device in communication with the filter monitor indicates a flow rate of the fluid through the filter. The differential pressure set point is additionally a function of the flow rate of fluid through the filter.