A method and device for facilitating maintenance of an anode of a marine engine cooling system, the device including a plug for an anode that has a detachable component with a threaded end for mounting to a threaded bore of a cooling system structure, a connector that holds the anode, at least one channel communicating with the cooling system and a sealing mechanism for sealing the channel from the cooling system, the sealing mechanism including a sealing element having an opening through which the anode may pass and being biased to seal against the anode and to close the opening to seal the channel when the anode is not present in the channel. The method permits changing the anode while preventing or minimizing water from exiting the cooling system of the marine engine.