Abstract: A method and system (10) for rerouting the pressurized oil flow of an engine (not shown) from a primary filter (14) to a secondary filter (18) in the event of a first sensed pressure differential across the primary filter (14) which exceeds an allowable pressure differential, the excessive differential indicative of a primary filter (14) obstruction. In the event of a subsequent second sensed pressure differential which exceeds a second and higher pressure differential across the secondary filter (18), the oil flow is then diverted through a pump relief valve (19) toward the oil reservoir (26), away from an engine bearing compartment (50). The system (10) also provides sequenced first and second level warnings (40, 42) to the controller/flight crew, said warnings responsive to the operating status of the system (10).