An engine assembly (10) for a propeller-driven aircraft is disclosed, the assembly including an engine (11), a drive shaft (13) driven by the engine (11), and a radiator (20) comprising an aperture (24) for receiving the drive shaft (13), the aperture (24) being located such that the radiator (20) substantially circumferentially surrounds the drive shaft (13). The aperture (24) may take various forms, such as a hole within the interior of the radiator (20) or a blind slit formed within the radiator (20).