Ducati MULTISTRADA 1200S ABS 2015 Workshop Manual page 108

Fill the circuit with new coolant through the water radiator plug.
Remove the clamp from the expansion reservoir/radiator pipe.
Wait several minutes for the coolant to fill all the internal passages.
Start the engine and wait for the coolant to reach 110 °C; run the engine for about 10 minutes.
Stop the engine and allow it to cool down so that all the air is expelled from the circuit.
Warning
Keep your hands, clothing and tools well clear of the radiator fan at all times; this fan starts automatically without
warning and could cause serious injury or damage.
Important
Check the circuit for possible leaks.
Top up the coolant through the expansion reservoir filler to bring the level up to the MAX. mark.
Refit the front half-casing (Refitting the front half-casing).