Is it possible to change the coolant liquid in a DeepCool AIO? If so, how often should it be changed? Is the AIO completely filled with coolant?

All DeepCool AIOs are prefilled from the factory, and should never require refilling for their serviceable life. We thoroughly test the units once they are filled and sealed. Our AIOs do not require internal maintenance of any form. In actuality, an AIO cannot be filled 100% with the coolant mix (antifreeze and special solvents) for numerous reasons, but there is usually a 5% air pocket in all AIOs.