1997 BMW 318i valv cover

GENERAL
......
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...
.
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.
.
.
117-1



Camshaft
timing
chains,
removing

(6-cylinder
engines)
....
.
....
..
....
..
...
.117-7
CAMSHAFT
TIMING
CHAIN,



Camshaft
timing
chains,
installing
4-CYLINDER
....
.
.
.
.
.
.
.
.
.
.
.
.......
.
...
117-2



6-clinderen
nes



117-11
Camshaft
timingchain,
removing



(



y



gi

(4-cylinder
engines)
...
..
....
..
...
...
....
117-2



VANOS
(VARIABLE
VALVE
TIMING)
.
..
117-14

Camshaft
timingchain,
installing



VANOS
system
operation,
testing
.....
.
....
117-14

(4-cylinder
engines)



...
..
...
....
..
.
.....
117-4



VANOS
control
unit,
removing
.
..
..........
117-16

CAMSHAFT
TIMINGCHAINS,



VANOS
control
unit,
installing
..
..
..........
117-17

6-CYLINDER
.
.........................
117-6

GENERAL

117
Camshaft
Timing
Chain

This
repair
group
covers
timing
chain
repair
information
for

the
4-
and
6-cylinder
engines
.

4-cylinder
enginesuse
one
double-row
chain
to
drive
the

dual
overhead
camshafts
.
See
Fig
.
1
.

Fig
.
1
.



M44
engine
valvetrain
chain
drive
.
M42
engine
is
similar
.

CAMSHAFT
TIMING
CHAIN



117-1

6-cylinder
enginesusetwo
chains
to
drive
the
camshafts
.
A

primary
chain
is
driven
off
the
crankshaft
and
drives
the
prima-

ry
sprocket
on
the
exhaustcamshaft
.
The
secondary
chain

drives
the
intake
camshaft
.
Each
chain
is
tensioned
by
a
hy-

draulic
tensioner
.
See
Fig
.
2
.

The
timing
chainsare
lubricated
by
engine
oil
and
do
not
re-`

quire
maintenance
.
A
worn
timing
chain
and
sprockets
can

lead
to
noisy
operation
and
erratic
valve
timing
.
A
faulty
ten-

sioner
can
also
cause
timing
chaín
noises
.

Primarychain

NOTE-

See
100
Engine-General
for
engine
code
and
applica-

tion
information
.

Secondary
chain
tensioner

Secondary
chain
B11115

Fig
.
2
.



Cutaway
view
of
camshaft
timing
chains
on1963
and
later
6-

cylinder
engine
with
VANOS
.

GENERAL

117-2



CAMSHAFT
TIMING
CHAIN

CAMSHAFT
TIMING
CHAIN,

4-CYLINDER

Special
BMW
service
tools
are
needed
for
timing
chain
re-
moval
and
installation
procedures
.
The
special
tools
assure

proper
timing
of
the
valvetrain
.
Precíse
marks
to
setthe
timing

on
the
camshafts
are
not
provided
for
reassembly
.
Read
the

procedures
through
before
beginning
the
job
.

CAUTION-

lf
the
camshaftsare
not
properly
timed,
the
pis-
tons
can
contact
thevalves
.

Camshaft
timing
chain,
removing

(4-cylinder
engines)
U0119-

Fig
.
3
.



Upper
timing
chain
covermounting
bolts(arrows)
.
Thermo-
1
.
Disconnect
negative
(-)cablefrom
battery
.



stat
housing
shown
removed
.
Cylinder
ídentification
sensor
(A)
also
shown
.

CAUTION-

Prior
to
disconnecting
the
battery,
read
the
battery
disconnection
cautions
given
at
the
front
of
this
manual
on
page
viii
.

2
.
Drain
engine
coolant
.
Drain
engine
block
byremoving
block
drain
.
Remove
radiator
cooling
fan
shroud
and
cooling
fan
.
See
170
Radiator
and
Cooling
System
..

WARNING
-

Allow
the
engine
to
cool
before
openingor
draining
the
cooling
system
.

CA
UTION-

On
cars
with
viscous-type
fan
clutch,
fan
has
left
hand
threads
.

NOTE-

The
block
drain
plug
is
located
on
the
exhaust
sideof
the
engine,
below
cylinder
no
.
4
.

3
.
Remove
cylinder
head
cover
.
See
113
Cylinder
HeadRemoval
and
Installation
.

NOTE-

Make
note
of
the
arrangement
of
the
rubber
insulators
when
removing
the
cylinder
head
cover
mounting
belts
.

4
.
Loosen
sparkplugs
.
See
120
Ignition
System
.

5
.
Disconnect
coolant
hoses
from
thermostat
housingon
front
of
cylinder
head
.
Unbolt
thermostat
housing
from
cylinder
head
.

6
.
Remove
cylinder
identification
sensor
from
upper
tim-
ing
chain
cover
.
Remove
upper
timing
chain
cover
.
See
Fig
.
3
.

CAMSHAFT
TIMING
CHAIN,
4-CYLINDER

7
.
Set
engine
to
approximate
TDC
by
rotating
in
normal
operating
direction
until
camshaft
lobes
at
cylinder
no
.

1
are
facing
up
and
toward
each
other
.
See
Fig
.
4
.

0011998
Fig
.
4
.



Engine
set
to
approximate
TDC
.
Cylinder
no
.
1
camshaft
lobes
face
in
and
sprocket
arrows
point
up
(arrows)
.

8
.
Remove
air
conditioning
drive
belt
.
Loosenand
push
aside
air
conditioning
compressor
.
Remove
air
condi-
tioning
compressor
mounting
bracket
.
See
640
Heat-
ing
and
Air
Conditioning
.

9
.
Remove
engine
drive
belts
and
coolant
pump
pulley
.
See
020
Maintenance
Program
.

10
.
Secure
crankshaft
vibration
damper
to
prevent
crank-
shaft
from
turning
.
Using
a
socket,
loosen
vibration
damper
hub
center
bolt
.

NOTE-

The
vibration
damper
center
bolt
is
very
tight
.
A
heavy
duty
holding
device,
such
as
BMW
special
tool
no
.
112
150,
should
be
used
to
hold
the
vibration
damper
hub



V
stationary
while
the
bolt
is
loosened
.
v

11
.
Usingloosened
bolt
at
vibration
damper,
turn
crank-

shaft
to
TDC
and
lock
in
position
by
inserting
BMW

special
tool
no
.
11
2
300
through
transmission
bell-



-



p

housing
.
See
Fig
.
5
.



v

O

NOTE-



I\



0011966a

"
If
necessary,
remove
plugfrom
locating
boye
in
lower
edge
of
bell
housing
.

"
Confirm
that
locatng
tool
has
been
correctlyinstalled
by
trying
to
rotate
the
crankshaft
.

Fig
.
7
.



Lower
timing
chain
cover
mounting
bolts
(arrows)
.
Bolts
A

Fig
.
5
.



BMW
special
tool
no
.
11
2300
installed
through
bellhousing



are
installed
through
hollow
locating
dowels
.

and
finto
flywheel
to
lock
crankshaft
at
TDC
(arrow)
.

CA
UTION-

Thecamshafts
mustbe
locked
in
the
MC
position
using
the
specialservice
tool
before
removing
the
timing
chain
.
The
tool
holds
the
camshafts
parallel

to
each
other
and
perpendicular
to
the
valve
cover
gasket
surface
.

12
.
Lockcamshafts
at
TDC
bymounting
BMW
special
tool

no
.
113
240
over
square
ends
of
camshafts
.
See
Fig
.
6
.

"
Check
that
tool
is
squarely
seated
on
cylinder
head

gasket
surface
.
If
necessary,
rotate
camshafts
slightly

using
an
open-end
wrench
at
hexon
camshafts
.

13
.
Remove
lower
timing
chaincover
mounting
bolts
and

carefully
lift
cover
off
.
Clean
sealing
surfaces
and
gas-

ket
grooves
.
See
Fig
.
7
.

14
.
Remove
hydraulic
chaintensioner
from
right
side
of
cyl-

inder
head
.
See
Fig
.
8
.

CAMSHAFT
TIMING
CHAIN



117-
3

Fig
.
6
.



BMW
special
tool
no
.
11
3240
installed
on
rearof
camshafts
to
position
camshafts
at
TDC
.
(M44
camshafts
shown
.
Other
engines
are
similar
.

Fig
.
8
.



Hydraulic
chain
tensionerplug
(arrow)
.

CAMSHAFT
TIMING
CHAIN,
4-CYLINDER

117-
6



CAMSHAFT
TIMING
CHAIN

15
.
Insta¡¡
upper
timing
chaincover
:



17
.
Remove
crankshaft
locking
tool
from
transmission
bell-

"
Thoroughly
clean
profile
gasketgroove
and
all
sealing



housing
and
camshaft
locking
tool
from
rear
of
cylinder

surfaces
.



head
.

"
Applya
small
bead
ofsilicon
sealer
(3-Bond
1209®
or

equivalent)
to
upper
and
lower
joint
comers
where



18
.
Turn
engine
over
by
hand
in
direction
of
rotation
at
least

chaincover
meets
cylinder
head
.



two
full
rotations
.
Reinstall
camshaft
and
crankshaft

"
Insta¡¡
new
profile
gasket
to
groove
in
lowerchain
cover
.



locking
tools
to
check
engine
timing
.
Repeat
cam
timing

"
Protect
top
of
profile
gasket
using
thin
sheetmetal



procedure
if
tools
do
not
fit
easily
into
position
.
Remove

(BMW
special
tool
no
.
11
2
330
or
equivalent)
.
See



locking
tools
.

Fig
.
15
.
"
Attach
new
gaskets
to
cover
with
light
dabs
of
gasket



19
.
Install
cylinder
head
cover
as
described
in
113
Cylin-

sealant,
hold
gaskets
in
placeusing
cover
mounting



der
HeadRemoval
and
Installation
.

screws
.

"
Place
upper
timing
cover
into
position
.
Snug
down
al¡



NOTE-
screws,
without
tightening
.
Carefully
slide
out
sheet



OnM44
engines,
note
oil
supply
O-ring
and
replace
ff
metal
.



necessary
.
"
Temporarily
install
cylinder
head
cover
without
gasket
.

Insta¡¡
and
tighten
at
least
two
cylinder
head
cover
mounting
bolts
to
seat
upper
timing
chaincover
.
"
Tighten
all
upper
timing
cover
screws
.



Tightening
Torque

"
Remove
valve
cover
.



"
Cylinder
head
cover

to
cylinder
head
(M6
screws)
...
..
.
.
10
Nm
(89
ín-Ib)

-



CAMSHAFT
TIMING
CHAINS,
Fig
.
15
.
When
installing
upper
timing
chain
cover,
use
thin
sheetmetal



6-CYLINDER
(arrow)
to
protect
profile
gasket
when
installing
uppercover
.

Tightening
Torque

"
Upper
timing
chaincover
to
engine
block
or
cylinder
head
(M6
screws)
....
.
..
10
Nm
(89
in-lb)

16
.
Install
vibration
damper
while
aligning
woodruff
key
.
Hold
crankshaft
stationary
and
tighten
mounting
bolt
.

Tightening
Torques



I
CAUTION-

"
Pulley
to
vibration
damper
..
.
.
.
....
22
Nm
(17
ft-Ib)



lf
the
camshaftsare
not
properly
timed,
the
1
pis-
tons
can
contact
thevalves
.
"
Vibration
damper
tocrankshaft
M16
stretch
bolt
(always
replace)
.
330
Nm
(244
ft-Ib)

CAMSHAFT
TIMINGCHAINS,
6-CYLINDER

20
.
Installation
of
remaining
parts
is
reverse
of
removal
.
When
installing
thermostat,
make
sure
arrow
or
vent
hole
faces
up
.
Refill
cooling
system
as
described
in
170
Radiator
and
Cooling
System
.

Tighteníng
Torques

"
Coolant
drain
plug
to
cylinder
block
.
..
.
.
.
...
.
..
.....
25
Nm
(18
ft-Ib)

"
Radiator
cooling
fan

to
coolant
pump
.
..
.
...
...
..
.....
40
Nm
(30
ft-Ib)

"
Radiator
drain
screw
to
radiator
....
2
.5
Nm
(22
in-lb)

Camshaft
timing
chainremovalon
6-cylinder
engines
re-
quires
that
you
Rmove
the
engine
oil
pan
by
raising
the
en-
gine
and/or
lowering
the
front
suspension
crossmember
.

Special
BMW
service
tools
are
needed
for
timing
chain
re-
moval
and
installation
procedures
.
The
special
tools
assure
proper
timing
of
the
valvetrain
.
Precise
marks
to
setthe
timing
on
the
camshafts
arenot
provided
for
reassembly
.
Read
the
procedures
through
before
beginning
thejob
.

117-
1
0



CAMSHAFT
TIMING
CHAIN

21
.
On
1993
and
lates
engines
:
Remove
access
plugs
from



24
.
On
1993
and
later
engines
:

VANOS
control
unit
in
front
of
exhaust
camshaft



"
Remove
VANOS
control
unit
as
described
laterinthis
sprocket
.
Remove
4
bolts
from
exhaust
camshaft



repair
group
.
sprocket
(useTono
El0
socket)
.
See
Fig
.
26
.



"
Remove
intake
camshaft
sprocket
mounting
nuts
.

"
Remove
intake
and
exhaust
sprockets
together
with

secondary
chain
.
Note
location
of
thrust
washers
and

spring
plate
(where
applicable)
on
intake
sprocket
.

Fig
.
26
.
Exhaust
camshaftmounting
bolts
(arrows)
.

CAMSHAFT
TIMING
CHAINS,
6-CYLINDER

0013056

22
.
Depress
secondary
timing
chain
tensiones
and
lock

down
by
inserting
stiff
wire
into
the
openings
in
rear
of
tensioner
.
See
Fig
.
27
.

Fig
.
27
.
Secondary
timing
chaintensioner
being
locked
down
on
M50
engine
.
Press
tensioner
downand
insert
locking
wire
through
holes(arrows)
.
Tensioner
on
M52/S52
US
engines
vary
slight-

23
.
Remove
secondary
chain
tensioner
and
lift
out
primary
chain
guide
.

NOTE-

Hold
the
camshaft
stationary
(at
hex
on
camshaft)
when
loosening
ortightening
sprocket
mounting
boits
.

CAUTION-

The
crankshaft
must
not
be
allowed
to
rotate
once
the
timing
chain
is
removed
.
The
pistons
can
con-
tact
the
valves
.

25
.
On
1992
engines
:

"
Remove
from
intake
and
exhaust
sprocket
mounting

bolts
.
"
Remove
sprockets
together
with
secondary
chain
.

26
.
Remove
bolts
holding
lower
timing
chain
cover
to
cylin-

der
head
(use
Torx
E8
socket)
.
See
Fig
.
28
.

MR111:
R

Fig
.
28
.
Cylinderhead-to-timingchain
covermounting
bolts
(arrows)
.

27
.
Using
a
drift,
drive
two
locatiog
dowels
in
left
and
right

sides
of
lower
timing
chaincover
toward
rear
of
car
.
Re-
move
covermounting
boits
and
carefully
lift
cover
off
.
See
Fig
.
29
.

CA
UTION-

Use
care
when
removing
the
cover
from
the
cylin-
der
head
gasket
.
If
the
cover
is
stuck,
useasharp
knife
to
separate
it
from
the
head
gasket
.

9)
B11126

Fig
.
29
.
Lower
timing
chain
cover
mounting
bolts
(arrows)
anddowel
locations
(A)
.
Coolant
hose
fitting
B
is
replaced
by
coolant
pipe
pressure
fitting
in
later
models
.

28
.
Remove
remaining
Torx
bolt
from
timing
chain
guide
.

See
Fig
.
30
.

Fig
.
30
.
Timing
chainguide
mounting
bolt(A)
.

CAMSHAFT
TIMING
CHAIN



117-
11

29
.
Lift
primary
chain
sprocket
off
exhaust
camshaft
and
remove
chain
.

NOTE-

"
If
any
of
the
sprockets
are
being
replaced
due
to
wear,
the
chain
should
also
be
replaced
.

"
If
the
crankshaft
sprocket
requires
replacement,
the
oil
pump
drive
sprocket
and
chain
must
be
removed
as
described
under
119
Lubrication
System
.

Camshaft
timing
chains,
installing

(6-cylinder
engines)

Inspecttiming
chainsprockets
.
Sprockets
that
haveworn
or

missing
teeth
should
be
replaced
.
Inspect
guide
rail
and
ten-

sioner
rail
for
deep
grooves
caused
by
chain
contact
.
Replace
any
parí
that
is
worn
.

The
procedure
outlined
below
assumes
that
the
camshafts

and
the
crankshaft
are
locked
in
the
TDC
installation
position

with
special
tools
(shown
earlier
in
Fig
.
23
and
Fig
.
24)
.

NOTE-
NOTE-



On
pre-VANOS
engines
(engines
built
up
to
8-92),
the

"
The
timing
chain
cover
can
be
removed
with
the
cool-



camshaft
locking
tool
(Fig
.
24)should
be
raised
upon

ant
pump
installed
.



eitherside
by
3mm
(use
feeler
gauge
or
dril¡
bits)
.
Be
sure
the
clamping
bolts
on
tool
are
loose
and
thecenter

"
Use
care
when
removing
the
chain
cover
from
the



of
the
tool
is
contacting
the
cylinder
head
surface
.
This

coolant
pipe
or
hose
at
the
rearof
the
cover
.



service
campaign
helps
improve
idle
characteristics
by
reducing
valve
overlap
.

1
.
Install
primary
timing
chain
to
crankshaft
sprocket
and

tie
it
up
through
cylinder
head
opening
.

2
.
Using
new
gaskets
and
coolant
pipe
O-ring
;
insta¡¡
low-

ertiming
chain
cover
:

"
Drive
timing
cover
doweis
inuntil
they
just
protrude

slightly
from
sealing
surface
.
"
Apply
a
small
bead
of
silicon
sealer
(3-Bond
1209
©
or

equivalent)
to
corners
of
cylinder
head
where
timing

cover
meets
cylinder
head
and
engine
block
.

"
Tap
cover
into
position
to
engage
doweis
.

"
Install
mounting
bolts
hand
tight,
including
two
outer

Torx
bolts
from
above
.

"
Drive
doweis
in
flush
to
front
of
cover
.

"
Tighten
cover
mounting
bolts
alternately
and
in
stages
.

Tightening
Torque

"
Lower
timing
cover
to
cylinder
block

M7
................
...
..
.
.....
15
Nm
(11
ft-Ib)

M8
.............
.
.
...
.........
20
Nm
(15
ft-Ib)

3
.
Insta¡¡
oil
pan
using
a
new
gasket
.
See
119
Lubrication

Systern
.

CAMSHAFT
TIMINGCHAINS,
6-CYLINDER

117-
1
4



CAMSHAFT
TIMING
CHAIN

22
.
Installation
of
remaining
parts
is
reverse
of
removal,



When
theengine
is
running,
the
piston
housing
is
supplied

noting
the
following
:



with
pressurized
engine
oil
.
At
idie,
the
solenoid
isin
the
off

"
When
installing
thermostat,
make
sure
arrow
or
vent



position
(de-energized)
and
valve
timing
is
maintained
in
the

hole
faces
up,
if
applicable
.



normal
position
:
When
the
solenoid
is
energized,
the
gear
cup

"
Refill
cooling
systemas
described
in
170
Radiator



piston
moves
forward
to
advance
the
camshaftby
a
maximum

and
Coming
System
.



of
12
.5
.

"
Install
oil
pan
as
described
in
119
Lubrication
Sys-

tem
.
"
Fill
engine
with
oil
and
install
a
new
oil
filter
as
de-

scribed
in
020
Maintenance
Program
.

"
Insta¡¡
ground
wires
at
cylinder
head
cover
mounting

studs
and
at
front
of
cylinder
head
and
thermostat

housing,
where
applicable
.



VANOS
system
operation,
testing

Tightening
Torques



There
are3
special
tools
required
to
check
VANOS
opera-

"
Coolant
drain
plugto
cylinder
block
.
.
25
Nm
(18
ft-Ib)



tion
;
an
electricaltest
lead
(BMW
special
tool
no
.
12
6
410),
an

"
Radiator
cooling
fan
to
coolant
pump
.
40
Nm
(30
ft-Ib)



air
line
fitting
(BMW
special
tool
no
.
11
3
450),
and
a
crank-

"
Radiator
drain
screw
to
radiator
...
.
2
.5
Nm
(22
in-Ib)



shaft
TDC
locking
tool
(BMW
special
tool
no
.
112
300)
.

"
Upper
timing
chaincover
to
cylinder
head



The
test
leal
is
used
to
power
the
solenoid,
simulating
the
M6
nut
...
.....
.............
..
.
10
Nm
(89
in-lb)



ground
signal
from
the
DME
control
unit
.
The
air
line
fitting
M8
bolt
.....
....
.
.
.............
22
Nm
(17
ft-Ib)



takes
the
place
of
the
oil
supply
line
fitting
to
simulate
oil
Ares-
"
VANOS
control
unit
to
cylinder
head



sure
.
The
locking
tool
positions
and
locks
the
crankshaft
at

M6
nut
.........
..
..
.
..........
10
Nm
(89
in-lb)



TDC,
cylinder
no
.
l.
M8
bolt
........
...
.............
22
Nm
(17
ft-Ib)

"
VANOS
oil
supply
pipe
to
VANOS
control
unit



1
.
Remove
alternator
cooling
air
duct
.

banjo
bolt
.......
..
..
.
..........
32
Nm
(24
ft-Ib)

VANOS
(VARIABLE
VALVE
TIMING)



3
.
Remove
top
plastic
enginecovers
.
Disconnect
ignition

coil
harness
connectors
fromcofs
.
Remove
ignition

1993
and
later
6-cylinder
engines
are
equipped
with
a
vari-



coils
.

able
valve
timing
system
called
VANOS
.
This
system
is
con-

trolled
by
the
engine
management
system
and
dynamically



4
.
Remove
cylinder
head
cover
mounting
bolts
and
re-

adjusts
intake
camshaft
timing
based
on
engine
load,
engine



move
cylinder
head
cover
.
Unclip
andremove
oil
baffle

speed
and
engine
temperature
.



cover
from
above
intake
camshaft
.
See
113
Cylinder

Head
Removal
and
installation
.

The
main
components
of
the
VANOS
system
are
the
control

unit
with
piston
housing
and
integral
spool
valve,
and
the
mod-

ified
intake
camshaft
.
See
Fig
.
35
.

VANOS
(VARIABLE
VA
LVE
TIMING)

Fig
.
35
.
VANOS
control
unit
with
modified
intake
camshaft
.

B11001

WARNING
-

Special
BMW
service
tools
are
required
to
check
and
repair
the
VANOS
System
.
Read
theproce-

dures
through
before
beginning
the
job
.

2
.
Disconnect
crankcase
ventilation
hose
fitting
from
cyl-

inder
head
cover
.

NOTE-

Note
the
arrangement
of
the
cylinder
head
cover
bolt
insulators
and
gaskets
during
removal
.

5
.
Set
engine
to
approximate
TDC
by
rotating
in
normal

operating
direction
until
camshaft
lobes
at
cylinder
no
.

1
are
facing
each
other
.
See
Fig
.
20
.

6
.
Set
engine
to
TDC
by
aligning
"0/T"
mark
(0°TDC)on

front
vibration
damper
withcast
boss
on
lower
timing
chain
cover
.
See
Fig
.
21
.

7
.
Lock
crankshaft
in
position
by
inserting
BMW
special

tool
no
.
11
2
300
through
transmission
bellhousing
and

into
hole
in
flywheelor
driveplate
.
See
Fig
.
36
.

NOTE-

Confirm
that
the
locking
tool
has
been
correctly
in-
stalled
by
trying
to
rotatethe
crankshaft
.

117-
1
6



CAMSHAFT
TIMING
CHAIN

15
.
Remove
crankshaft
locking
tool
.
Remove
special
test

equipment
.
Insta¡¡
oil
supply
line
using
new
seals
and

reconnect
solenoid
connector
.
Remainder
of
installa-

tion
is
reverse
of
removal
.

Tightening
Torque

"
Cylinder
head
cover
to
cylinder
head
.
10
Nm
(89
in-lb)

"
VANOS
oil
supply
line
to
VANOS

control
unit
(banjo
bolt)



..
.........
32
Nm
(24
ft-Ib)

"
VANOS
solenoidlo
VANOS

control
unit
........
.
.
.
..
........
30
Nm
(22
ft-Ib)

VANOS
control
unit,
removing

Special
BMW
service
tools
are
required
lo
remove
and
in-

stall
the
VANOS
control
unit
.
Read
the
procedure
through
be-

forestarting
the
job
.

1
.
Remove
radiator
cooling
fan
shroud
and
cooling
fan
.

See
170
Radiator
and
Cooling
System
.

CAUTION-

Radiator
fan
has
left
hand
threads
.

2
.
Remove
top
plastic
engine
covers
.
Disconnect
ignition

coil
harness
connectors
from
coils
.
Remove
ignition

coils
.
Remove
cylinder
head
cover
.
Unclip
andremove

oil
baffle
cover
from
above
intake
camshaft
.See
113

Cylinder
Head
Removal
and
Installation
.

NOTE-

Make
note
of
the
mounting
bolt
insulator
arrangement
during
removal
of
the
cylinder
head
cover
.

3
.
Set
engine
lo
TDC
by
rotating
engine
in
normal
operat-

ing
direction
until
camshaft
lobes
at
cylinder
no
.
1
are

facing
each
other
and
"0/T"
mark
(0°TDC)
on
vibration

damper
lines
up
with
cast
boss
on
lower
timing
chain
cover
.
See
Fig
.
38
.

4
.
Lock
crankshaft
at
TDC
by
inserting
BMW
special
tool

no
.
11
2
300
through
transmission
bellhousing
and
finto

flywheel
or
drive
plate
.
Refer
to
Fig
.
36
given
earlier
.

NOTE-

Confirm
that
the
locking
tool
has
been
correctly
in-
stalled
by
trying
to
rotatethe
crankshaft
.

5
.
Remove
three
cylinder
head
cover
mounting
studs
from
rear
of
head
.
Lockcamshafts
at
TDC
bymounting

BMW
special
tool
no
.
11
3
240
at
ends
of
camshafts
.

Check
that
tool
is
squarely
seated
on
cylinder
head
gasket
surface
.
If
necessary,
rotate
camshafts
slightly
using
a24
mm
wrench
.
Refer
to
Fig
.
24
given
earlier
.

VANOS
(VARIABLE
VALVE
TIMING)

Fig
.
38
.
Camshafts
positioned
at
TDC-Cyl
.
No
.
1
cam
lobes
face
in
Note
0/T
mark
(0°TDC)
on
vibration
damper
alígned
with
boss
on
front
cover
.

CA
UTION-

Thecamshafts
mustbe
locked
in
the
TDC
position
using
the
specialservice
tool
or
an
equivalent
be-
fore
removing
the
timing
chain
.
Thearrows
on
the
sprockets
should
not
be
used
to
accurately
set
the
engine
to
TDC
The
special
tool
holds
the
cam-
shafts
parallel
to
each
other
and
perpendicular
to
the
valve
cover
gasket
surface
.

6
.
Disconnect
harness
connector
and
oil
line
fitting
from
bottom
of
VANOS
control
unit
.

NOTE-

Wrap
the
VANOS
oilfine
fitting
with
a
shop
rag
to
ab-
sorb
leaking
oil
.

7
.
Remove
two
access
plugs
from
VANOS
control
unit
in
frontof
exhaustcamshaft
sprocket
.
Loosen
4exhaustcamshaft
sprocket
mounting
bolts
but
do
not
remove

(Torx
El
0
socket)
.

NOTE-

Removal
of
the
access
plugs
allows
the
lower
exhaust
camshaft
sprocket
mounting
bolts
to
be
accessed
.

8
.
Depress
secondary
timing
chain
tensioner
and
lock
it
in
down
position
by
inserting
a
stiff
wire
into
rear
of
ten-
sioner
.
See
Fig
.
27
.

9
.
Remove
VANOS
control
unít
mounting
nuts
and
boltat

front
of
cylinder
head
.