According to one aspect of the present technology, there is provided a snowmobile having: a tunnel; a motor; at least one ski; and a drive track. At least a portion of the tunnel is formed by a heat exchanger assembly having: a front portion; a middle portion; a rear portion; a top part; and a bottom part. The bottom part defines at least one recess. The top and bottom parts define therebetween a passage formed in part by the at least one recess. A first portion of the passage is defined by the at least one recess extending longitudinally. The drive track has: a plurality of lugs; and a plurality of studs. Portions of the plurality of lugs being laterally aligned with the first portion of the passage being free of studs.