Downloaded from www.Manualslib.com manuals search engine 39
N62 Engine
Coolant Circuit
The coolant flow has been optimized allowing the engine to warm up as quickly as possi-
ble after a cold start as well as even and sufficient engine cooling while the engine is run-
ning. The cylinder heads are supplied with coolant in a cross-flow pattern. This ensures
more even temperature distribution to all cylinders. The cooling system ventilation has been
improved and is enhanced by using ventilation ports in the cylinder heads and in the radi-
ator. The air in the cooling system accumulates in the expansion tank. When a pressure of
2 bar is reached in the expansion tank, the air is bled out by the pressure relief valve in the
reservoir cap.
N No
ot
te
e:
:
The ventilation ports in the front of the cylinder heads provide quicker “self bleeding”
during a routine coolant exchange. The complex cooling system and the small ventilation
ports require that time should be allowed after the cooling system has been filled for the air
to escape.
Coolant flow in the Engine Block
The coolant flows from the water pump through the feed pipe (1) in the engine's V and to
the rear of the engine block. This area has a cast aluminum cover (see following illustration).
From the rear of the engine, the coolant flows to the external cylinder walls and from there
into the cylinder heads.
The coolant then flows from the cylinder heads into the engine block V and through the
return connection (3) to the thermostat housing. When the coolant is cold it flows from the
thermostat (closed) directly into the water pump and back to the engine (recirculating for
faster warm up).
When the engine reaches operating tempera-
ture (85 ºC-110 ºC), the thermostat opens the
entire cooling circuit to include the radiator.
42-02-57
Engine Block Coolant Flow
1. Coolant from the water pump through the feed pipe
to the rear of the engine.
2. Coolant from the cylinder walls to the thermostat
housing.
3. Return connection to water pump/thermostat.
Downloaded from www.Manualslib.com manuals search engine 51
N62 Engine
Oil Filter
The canister type oil filter (3) is located under the
engine by the oil sump. The support for the oil
filter is integrated in the rear oil pump cover.
The oil filter housing (2 with o-ring) is threaded
into the rear of the oil pump cover through an
opening in the oil sump.
A A
d
dr
ra
ai
in
n
p
pl
lu
ug
g
i
is
s
i
in
nt
te
eg
gr
ra
at
te
ed
d
i
in
n
t
th
he
e
o
oi
il
l
f
fi
il
lt
te
er
r
h
ho
ou
us
si
in
ng
g
f fo
or
r
d
dr
ra
ai
in
ni
in
ng
g
t
th
he
e
f
fi
il
lt
te
er
r
a
as
ss
se
em
mb
bl
ly
y
b
be
ef
fo
or
re
e
t
th
he
e
h
ho
ou
us
s-
-
i in
ng
g
i
is
s
r
re
em
mo
ov
ve
ed
d
(
(1
1
w
wi
it
th
h
o
o-
-r
ri
in
ng
g)
).
.
The filter element support dome contains an over pressure relief valve. If the filter element
is blocked, this valve bypasses unfiltered engine oil around the element to the supply lubri-
cation to the engine.
Pressure Control
The oil pressure control valve in the oil pump has two functions:
1. Deactivates stage two oil pump circuit above 2 bar. Stage two is only active in the
lower speed range. This is to ensure that there is always sufficient oil pressure for
the VANOS units even at high oil temperatures and low speeds. The oil pump power
consumption is reduced by deactivating stage two.
2. Monitoring the required oil pressure for the engine. The piston in the control valve is
moved by a spring against the engine control pressure which is returning from the
engine. This means that precise monitoring of the actual engine oil pressure is pos-
sible.
A A
s
se
ep
pa
ar
ra
at
te
e
p
pr
re
es
ss
su
ur
re
e
r
re
el
li
ie
ef
f
v
va
al
lv
ve
e
i
in
n
t
th
he
e
o
oi
il
l
p
pu
um
mp
p
a
au
ut
to
om
ma
at
ti
ic
ca
al
ll
ly
y
o
op
pe
en
ns
s
a
at
t
t
th
he
e
m
ma
ax
xi
im
mu
um
m
p
pr
re
es
s-
-
s su
ur
re
e
o
of
f
a
ap
pp
pr
ro
ox
xi
im
ma
at
te
el
ly
y
1
15
5
b
ba
ar
r.
.
T
Th
hi
is
s
p
pr
re
ev
ve
en
nt
ts
s
d
da
am
ma
ag
ge
e
i
in
n
t
th
he
e
o
oi
il
l
p
pu
um
mp
p
e
es
sp
pe
ec
ci
ia
al
ll
ly
y
a
at
t
l
lo
ow
w
o
oi
il
l
t te
em
mp
pe
er
ra
at
tu
ur
re
es
s.
.
42-02-77
