A method for detecting a leak in a pump comprises: monitoring discharge pressure time domain signals of the pump; monitoring piston position time domain signals for each piston of a plurality of pistons; filtering the monitored discharge pressure time domain signals and the monitored piston position time domain signals of each piston of the plurality of pistons via a band pass filter; determining, at each pump revolution for each piston, a sum of product of the filtered discharge pressure time domain signals and the filtered piston position time domain signals; determine, at each pump revolution for each piston, an absolute value of each sum; determining, at each pump revolution, a largest absolute value of the determined absolute values; determining a corresponding piston of the plurality of pistons associated with the largest absolute value; and determining a cylinder of the pump associated with the determined corresponding piston as leaking.