oil separator symptoms
 

what are the clues or symptoms when it's about time to replace the oil separators?

oil separator
 

guys, i'm about to change my oil separator for a preventive purpose.

pls, tell me what i need to purchase from the attached diagram of the oil separator. cheers

anybody

All of them while you at it and dont foget the valve cover gasket too.

Here is what you need exactly for a 3.0I, the realOEM diagram is not totally correct. I got the usual OS (not the insulated one) as I'm living in hot climate.
As said above, you need the valve cover gasket too and also the throttle body gasket. I'd add too the dipstick tube o-rings (one large at the bottom, two small at the top)

What are the symptoms?

what's the part number for valve cover gasket and throttle cover gasket

Valve cover gasket: #16 on this diagram: RealOEM.com BMW E53 X5 3.0i Cylinder head cover

Can't find the throttle housing gasket in realOEM, here it is in the Pelican parts site: Pelican Parts - Product Information: 13-54-7-504-729-M17

Dipstick tube o-ring: #11 and 12 here: RealOEM.com BMW E53 X5 3.0i OIL PAN/OIL LEVEL INDICATOR

Search in this forum and you will find tons of information about OS. Most common symptoms are rough idle, major oil leak around the OS itself or to the valve cover gasket, codes for misfires and O2 sensors. Most of the OS separator problems occur in very cold climate but can occur too in hot climate with less annoying consequence though.

Would the separator throw out a code? Or would the mechanic need to manually inspect the vehicle?