Two things come to mind:

1. Cooling Overhaul. I did a partial overhaul at 115K, but at your mileage of 175K, do a complete overhaul.
I posted a DIY in forum.

2. CCV, don't replace the stock CCV, search for "BavarianE39 CCV Mod" using Duralast PCV valve, this reduces my oil consumption from 1qt/400 miles down to zero oil consumption.
I posted a photos in that infamous thread.

__________________
1998 E39 528i 5sp MT
2006 E53 X5 3.0 6sp MT