As Spazman noted you need not remove the intake(unless you suspect a vacuum leak). I just did it on my 940. I had to remove an EGR which was in the way also. After the whole procedure my theory is that it is not just the Oil Seperator which causes the problem it is the whole system. My Oil Seperator was probable "only" 30% blocked. But then the 4" tube that runs up from the separator to the Flame trap was literally 40% blocked(looked like a clogged artery)the flame trap had been changed somewhat recently but was still maybe 10-15% blocked. The metal nipple where the small flame trap house vents into the Intake was almost totally plugged. The orifice from the larger Flame trap hose into the bellows was 20-30% plugged(that even I was surprised at). And as noted the O-ring that seals the Oil separator to the block was rock hard and flattened(functionally useless). So while no one piece was totally to blame, the whole system needed to be thoroughly cleaned and or replaced. I now have suction at the oil filler cap and my rear main leak has slowed to barely seepage. Replace the separator and the Flame trap assembly(9$ at FCP and it come with everything).