There is disclosed a cooling system for a liquid cooled internal combustion power plant housed in an engine compartment in a tail cone of an aircraft. The cooling system has: a tail cone inlet defined through a wall of the tail cone and fluidly communicating with an environment; a wall inlet defined through a firewall of the engine compartment; a blower within the engine compartment and having a blower inlet and a blower outlet, the blower inlet fluidly communicating with the environment via the tail cone inlet, via the wall inlet, and via an interior of the engine compartment; a blower outlet defined through a wall of the aircraft and fluidly communicating with the environment; and a cooling flow path extending from the tail cone inlet to the air outlet and across the wall inlet, the cooling flow path in heat exchange relationship with the power plant.