In one embodiment, there is provided a dock for a replaceable fluid container for an engine, the fluid container having: a fluid reservoir; and at least one fluid port having a coupling adapted to couple with a fluid circulation system associated with the engine; the dock having: a fastening mechanism configured to cooperate with the container such that, as the container is inserted into the dock, the fastening mechanism acts first to seat the fluid container in the dock but in an undocked condition and then, as the container is inserted further into the dock, acts to bring the fluid container into an engaged condition in which the fluid container is docked with a docking interface of the dock.