Hello, my very first post here! I recently purchased a 2006 V70 - B5244S2 engine, 250 000 miles (400 000 kilometers). It looks pretty taken care of, drives decently, doesn't appear to be leaking or anything. However, today I noticed that the breather hose which goes from the oil separator to cylind...

I replaced by reaching under IM, no need to remove the IM.
Leave the cosmetic cover off the car (easier if you need access to the hose and ignition coils).
I wrote it in XC90 forum.
Similar idea turbo or non turbo.
Use only Genuine Volvo parts,

“Just Maybe” it would help to remove the throttle body and the intake duct (the throttle body may need to be cleaned anyway) and “Just maybe” you can reach your right hand/arm under the intake manifold to disconnect/reconnect the hose from the top of the separator box.