A snowmobile has a frame including a tunnel, at least one ski, an engine having an engine air inlet and a drive track operatively connected thereto and disposed at least partly below the tunnel around a rear suspension. A heat exchanger connected to the tunnel has a heat exchanger air inlet and a heat exchanger air outlet fluidly communicating with the heat exchanger air inlet and the engine air inlet. A snowmobile has a frame including an inverted U-shaped tunnel having top, left and right portions at least partly enclosing a space. A drive track, operatively connected to an engine, is disposed around a rear suspension and at least partly in the space. An air intake system has a heat exchanger surface disposed in or adjacent to the space. Air flowing through the intake system contacts the heat exchanger surface to be cooled thereby before entering the engine.