I'm not quite sure what one of these would look like applied to a crankcase exhauster application. After looking at the drawings showing the general arrangement for the air cleaner bleed air in the -7 and -8 service pubs, it looks like it would be all within the hood in either case.
The normal motor driven exhauster pipe does not always go up through the roof, however. I have seen them make a 180 bend and end up just above the rail on a few units; RS-3s come to mind, I just can't remember where.
The LIRR FA-2 power cars, which I am a bit familiar with, still have the "mushroom" fitting on the roof, but the pipe goes up, crosses over the walkway, and comes down along the side of the unit (inside). It then goes through the floor, follows the front of the fuel tank on the fireman's side, and ends just above the rail.
I can imagine that there would be many variations and railroad shop mods to that pipe. Having it end below the unit would help keep dirt, soot, oil, etc. off the roof and from running down the sides.
Funny that the 539s and the EMDS don't have exhausters (at least that I've seen on EMDS; I'm not as well versed on them), not have I seen exhausters on any GE or in any GE pubs. Seems to be a 244/251 thing-