Abstract: In construction vehicles (10) it is not uncommon to have the cab or operator's station (12) positioned directly adjacent the engine enclosure (14). Being so positioned, the transfer of the heat created by the engine (16) is often transferred directly into the confines of the cab (12) by a wall (28) of the cab (12). The wall construction (28) of this invention includes an air passage (41) in which a current of ambient air (49) is established within the wall (28). A pressure drop, which is created by an existing flowage of air (26) within the engine enclosure (14), is utilized to pull ambient air (49) from the cab interior (36) and through the air passage (41). The air moving through the passage (41) provides a cooling thereof to prevent the transfer of heat from the engine enclosure (14) to the cab interior (36).