Hello, I'm Jason. I will do my best to answer your question quickly and accurately using the information you have provided.
Good to hear that you replaced the separator already...
I'm 95% positive that your leak is coming from the oil filter housing to block gasket
extremely common oil leak area on any M54 engine
I'll hold chat open if you have any questions about it
Ah, looks like you made it into chat
Is this a DIY fix or should I take it to a mechanic?
Well, that one is somewhat impossible for me to answer, as I don't know your mechanical abilities. It's about a 4 hour job for a DIYer, and on a scale of 1-10 with 10 being the most difficult fix, I'd place this at a 6 or so
Air filter box, alternator, power steering pump, belt, and left side belt accessory bracketry needs to be removed to access the filter housing bolts
here is the gasket
Well, I replaced the oil separator myself along with the valve cover gasket and would rate the oil separator and removal and cleaning of the intake system a 9-10. I have the proper tools as well as a lift.
if you did the separator, then this will be easy for you. Hate to offer this in hindsight, but the separator is ridiculously easy once the filter housing is off. I usually try to sell both jobs together, and save a lot of labor for my customers that way
Remove fan shroud, belt, alternator, PS pump with bracket, and you're staring at the filter housing
I'm sure you'll do fine
Will do, Thanks for your help.