Systems and techniques that facilitate predictive core rub diagnostics are provided. A sensor component can collect real-time operation parameters of a gas turbine engine. An analysis component can statistically combine first values, second values, and third values to yield a rub indicator for the engine. The first values can be based on a first comparison of fundamental mode placements of the engine, derived from the real-time operation parameters, and baseline fundamental mode placements. The second values can be based on a second comparison of a vibration spectrum of the engine, derived from the real-time operation parameters, and a baseline vibration spectrum. The third values can be based on a third comparison of the real-time operation parameters of the engine and baseline operation parameters. A classification component can generate a rub classification report indicating presence of rubbing in the engine, based on the rub indicator.