BMW S58 Owner's Handbook Manual page 26

S58￿Engine
4.￿Engine￿Mechanical
The￿blow-by￿gases￿pass￿through￿the￿opening￿in￿the￿area￿of￿no.￿6-cylinder￿into￿the￿settling￿chamber
in￿the￿cylinder￿head￿cover.￿From￿the￿settling￿chamber,￿the￿blow-by￿gases￿pass￿through￿the￿particle
separator￿with￿ball￿valve￿where￿they￿are￿separated￿from￿the￿oil￿by￿an￿artificial-felt￿element.￿The￿blow-
by￿gases￿separated￿from￿the￿oil￿next￿pass￿either￿through￿the￿crankcase￿vent￿valve￿via￿the￿cylinder￿head
into￿the￿intake￿area￿upstream￿of￿the￿intake￿valves￿or￿to￿the￿intake￿area￿upstream￿of￿the￿turbocharger,
depending￿on￿the￿engine￿operating￿mode.￿The￿separated￿oil￿is￿directed￿via￿a￿return￿duct￿discharging
into￿the￿sump￿below￿the￿oil￿level.￿A￿non-return￿valve￿in￿the￿lower￿part￿of￿the￿crankcase￿in￿the￿area￿of￿the
sump￿ensures￿that￿no￿oil￿from￿the￿sump￿can￿pass￿into￿the￿crankcase￿ventilation￿system￿from￿the￿sump.
The￿precise￿procedure￿for￿removing￿and￿installing￿the￿cylinder￿head￿cover￿can￿be￿found￿in￿the￿up-to-
date￿information￿in￿the￿BMW￿workshop￿system￿ISTA.
Operating￿principle
The￿standard￿function￿can￿only￿be￿utilized￿while￿there￿is￿a￿vacuum￿in￿the￿intake￿plenum,￿i.e.￿in￿naturally
aspirated￿mode.
In￿naturally￿aspirated￿mode,￿the￿crankcase￿vent￿valve￿and￿the￿ball￿valve￿in￿the￿particle￿separator￿in￿the
cylinder￿head￿cover￿are￿opened￿by￿the￿vacuum￿in￿the￿intake￿plenum.￿The￿blow-by￿gases￿are￿routed￿via
the￿distributor￿rail￿integrated￿in￿the￿cylinder￿head￿cover￿directly￿into￿the￿cylinder￿head￿intake￿ports.
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