A method to dislodge an adherent residue in an EGR cooler, the EGR cooler installed in an engine. The method comprises switchably flowing the exhaust gas through the exhaust-gas recirculation cooler according to a normal-calibration control mode when a temperature of the coolant is above a threshold temperature, and switchably flowing the exhaust gas through the exhaust-gas recirculation cooler according to an EGR-cooler restoring control mode (with a greater time-averaged flow of the exhaust gas) when the temperature of the coolant is below the threshold temperature.