The line that runs from the bottom of the air-intake hose (the large, maybe 3 inch diameter hose from the air box) to the throttle body has a bayonet connector on it that often gets clogged. It is from here that the line runs to the oil separator. Use a pipe cleaner...one of thse with the brissles dipped in alcohol to clean out the connector part really well. I did the same pcv hose and related item replacment and still had a "clogged" system until I cleaned that connector out. Also, in your case make sure the flame trap is clean. You might consider throwing away the flame trap all together and just having an empty flame trap holder in your lines. Either way, attempting to tighten down your dip-stick with better vacuum, etc. will surely cause a blow-out somewhere else if you have excessive crankcase pressure, so I wouldn't worry about getting a good seal there. Good luck!
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1998 S70 T5 Emarald Green Metallic, 2004 V70 2.5T Ruby Red, Previous Owner of Black '94 850 Turbo Wagon. My cars have been running so well lately they've got me worried.