To expel the hot air, the fin of the engine cover of the Mercedes has been cut and widened (see the white arrows). This was already the case last season, although the opening is shorter than on the W08 as the long “shark fins” have since been banned. In addition, gill-shaped inlets (yellow arrows) were made in the body below the Halo side clips. This opening evacuates the hot air coming out of the radiators (red arrow).
Similar grills have been used by the majority of the teams: Red Bull, Ferrari (which made an extra opening in the cockpit – see blue arrow), McLaren, Toro Rosso, Force India, and so on.
Notice that on the cars of Esteban Ocon and Sergio Perez, the openings were already present. The version introduced in Bahrain keeps the same length, but has only five fins instead of nine previously.