The hose that goes from separator to dipstick completely rotted off
on mine! Lots of oil. It was a pain in the azz to get it back in.
Can be done with intake manifold still on. Some write ups around on
the E46 fanatics website.
I did all hoses and the one on the top along the intake manifold.
There is an upgrade to bottom hose, now insulated, before just a little
braid insulation.

I'm still getting a slow oil leak. Seems to be Oil filter housing. $5 gasket
goes bad it seems. Dealers tell you that you need a new housing for $450.

BTW I'm at 204K and counting miles wise!