While adding some oil to my N62 last week, I noticed that the filler cap was askew. It wouldn't turn enough to be "square" in its place. I also noticed that there was oil seepage down the top of the valve cover below the cap, blow by pressure must have obviously pushed some oil out. I ordered a new OEM cap from a BMW dealership in SF on Amazon. Put it on today, a quarter turn, fit squarely.

It made me think, is there any chance that my seller installed an ill-fitting oil cap to reduce pressure that might reduce Valve stem seal seepage and the resultant smoking at idle during my pre-purchase inspection? ...Or do I "know just enough to be dangerous?" Thanks!

2008 X5 4.8i 167k miles

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'08 X5 4.8i
'98 328iC 5spd
'95 540i 6spd
'89 325i 5spd
'89 535i 5spd
'87 325e 5spd
'73 2002 4spd