Create the fans by dragging out a cylinder in the top view about the size of the can then convert it to an editable mesh select the top polygon and bevel it so it is about the right size. Hold down Shift and drag it over to make copies of it for the other fans. (fig.19, fig.20)
fig.19
fig.20
I seemed to have over looked a part! the stepped up platform or whatever you want to call it, it will be easy to add it in, you should add this in earlier though normally before the cab.
Start off by dragging a box out in the side view that matches it to the best you can then convert it to editable mesh and make any more adjustments that may be needed. Select the cab and go into vertex sub-object mode and pull the bottom up so it rest on top of the box we just created. (fig.21, fig.22)
fig.21
fig.22
Now for the Steps, create a box as shown in the screenshot and adjust it as needed then clone it over once as shown in the screenshot, the little wings on the front box or whatever you want to call them I created those by using the slice modifier then extruding the polygons out some. (fig.23, fig.24)
