If you pull the hose off the CCV to the dipstick tube and apply a low pressure air shot to it, with the dipstick partially lifted, is it blocked there? You can attach a length of extra vinyl hose so you don’t have to stand on your head the whole time. If it’s clogged and breaks free, you can do the Seafoam down that tube and oil change to see if you solved your problem.

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2001 x5 3.0 (sold with broken motor), 1990 e30 M3, 1991 318is, 2002 325i, 2008 335i Dinan stage 3 6 speed,