An engine assembly including an internal combustion engine configured to be received in an engine compartment and a heat exchanger having a first conduit fluidly connected to a fluid circuitry of the engine and a second conduit fluidly connecting an interior of the engine compartment to its environment. The first conduit is in heat exchange relationship with the second conduit. The assembly further includes a forced air system operable in use to provide an air flow from the environment to the outlet via the second conduit of the heat exchanger and the engine compartment. The assembly further includes a selector valve configurable to selectively fluidly connect an air intake of the internal combustion engine with the interior of the engine compartment in a first valve position and with the environment in a second valve position. A method for supplying air to an internal combustion engine is also discussed.