1994 BMW 325i Engine oil service
[x] Cancel search: Engine oil servicePage 85 of 759
GENERAL
CYLINDER
HEAD,
DISASSEMBLY
AND
ASSEMBLY
CYLINDER
HEAD
AND
VALVETRAIN
116-1
116
Cylinder
Head
and
Valvetrai
n
GENERAL
.
.....
.
.
.
...
.
.
.
.
.
.
.
.
.
.......
116-1
Hydraulic
cam
followers,
checking
and
replacing
(M42
and
al¡
6-cylinder
engines)
.
...
.....
.
..
116-9
CYLINDER
HEAD,
Valve
guides
.
.
.
...
.
.
.
.
.
.
...
.
.
.
.
.
.
.
.
.
.
116-10
DISASSEMBLY
AND
ASSEMBLY
...
.
...
116-1
Valves
.
.
.
.
.
.
.
.
.
.
.
.
.
...
.
...
.
.
.
.
.
...
.
.
116-11
Camshafts,
removing
and
installing
(M42
engine)
....
.
....
.
.
.
.
.
.
.
.
.
.....
.
.
116-1
Valves,
leak
test
.
.
.
.
.
.
.
.
.
.
...
.
.
.
.
.
.
.
.
.
.
116-11
Camshafts,
removing
and
installing
Valve
stem
oil
seals
.
.
.
.......
.
.
.
.
.
...
.
.
116-11
(M44
engine)
.........
.
.
.
.
.
.
.
.
.
.......
116-3
Valve
seats
.
.
.
.
.
.
.
.
.
...
.
...
.
.
.
.
.
...
.
.116-12
Camshafts,
removing
and
installing
Valve
springs
.
.
.
.
.
.
.
.
...
.
...
.
.
.
.
.
.....
116-12
(6-cylinder
engine)
.....
.
.
.
.
.
.
.
.
.
.......
116-4
Valves,
removing
and
installing
........
.
....
116-6
TABLES
CYLINDER
HEAD
AND
VALVETRAIN,
a
.
Cylinder
Head
Height
........
....
.
..
..........
116-7
RECONDITIONING
.
...
.
.
.
.
.
.
.
.
.
.......
116-7
b
.
Camshaft
Specifications
.......
..
.
..
........
.116-7
Cylinder
head
...
.
.
.
...
.
.
.
.
.
.
.
.
.
....
.
..
116-7
c
.
Valve
Guide
Specifications
....
...
.
..
........
116-10
d
.
Valve
Specifications
...........
..
.
..
........
116-11
Camshaft
.
.
.
.
.
.
.
.
.
.
.
.
.
.
...
.
.
.
.
.
.......
116-7
e
.
Valve
Seat
Dimensions
.........
.
..
..
......
.116-12
Hydraulic
valve
adjusters,
checking
and
replacing
(M44
engine)
..
.
.
.
116-8
Camshafts,
removing
and
installing
(M42
engine)
This
repair
group
covers
cylinder
head
and
valvetrain
ser-
vice
and
repair
.
Most
of
the
repairs
described
here
require
that
The
camshafts
can
be
removed
with
the
cylinder
head
the
cylinder
head
first
be
removed
as
described
in
113
Cylin-
mounted
on
the
engine
.
The
first
step
is
to
remove
the
cylinder
der
HeadRemoval
and
Installation
.
head
cover
.
See
113
Cylinder
HeadRemoval
and
Installa-
tion
.
NOTE-
Special
BMW
service
tools
should
always
be
used
to
remove
"
For
timing
chain
and
VANOS
repair
information,
see
and
install
the
camshafts
.
Removal
and
installation
of
the
cam-
117
Camshaft
Timing
Chain
.
shafts
without
the
special
tools
can
result
in
camshaft
and
valve
"
If
it
is
determined
that
the
cylinder
head
will
require
train
damage
.
significant
reconditioning
work,
a
remanufactured
cyl-
inder
head
may
bea
good
alternative
.
Remanufac-
WARNING-
tured
cylinder
heads
are
available
froman
authorized
The
process
of
evenly
loosening
the
camshaftbear
BMW
dealer
.
ing
cap
nuts
is
NOT
an
acceptable
method
of
re-
moving
the
camshafts
.
Be
sure
to
read
the
The
information
given
in
this
repair
group
is
organized
ac-
procedure
through
before
starting
the¡ob
.
cording
to
engine
code
.
For
engine
applicationinformation,
see100
Engine-General
.
1
.
Disconnect
negative
(-)
battery
cable
.
CAUTION-
Prior
to
disconnectiog
the
battery,
read
the
battery
disconnection
cautions
given
at
the
front
of
this
manualonpage
viii
.
BMW
special
tools
are
required
for
most
cylinder
head
ser-
2
.
Remove
radiator
cooling
fan
shroud
and
cooling
fan
.
vice
described
in
this
repair
group
.
Many
of
these
tools
areex-
See
170
Radiator
and
Cooling
System
.
pensive
and
only
available
through
an
authorized
BMW
dealer
.
If
the
special
tools
are
not
available,
one
altematve
is
to
remove
the
cylinder
head
and
have
it
disassembled
byan
authorized
CAUTION-
BMW
dealer
.
Be
sure
to
read
each
procedure
thoroughlybefore
Radiator
fa
n
has
left
hand
threads
.
starting
a
job
to
determinewhich
special
tools
and
equipment
will
be
necessary
.
CYLINDER
HEAD,
DISASSEMBLYANDASSEMBLY
Page 91 of 759
CYLINDER
HEAD
AND
VALVETRAIN,
RECONDITIONING
Thís
section
provides
the
specifications
and
special
recon-
ditioning
information
necessary
to
repair
the
cylinder
heads
covered
by
this
manual
.
If
machine
shop
services
are
not
readily
available,
one
al-
ternative
is
to
install
a
remanufactured
cylinder
head
froman
authorized
BMW
dealer
.
Cylinder
head
NOTE-
When
replacing
the
cylinder
headon
engines
with
re-
movablecamshaft
carriers,
be
sure
to
check
the
cam-
shaft
carrier
bearing
surfaces
for
warpage
.
4-cylinder
1
140
.0
mm
(5
.512
in)
1
139
.55
mm
(5
.494
in)
6-cylinder
1
140
.0
mm
(5
.512
in)
1
139
.7
mm
(5
.500
in)
CYLINDER
HEAD
AND
VALVETRAIN
116-
7
A
The
disassembled
cylinder
head
should
be
inspected
for
Fig
.
9
.
Front
víew
of
cylinder
head
showing
minimum
resurfacing
di-
warpage
and
cracks
.
Check
the
valve
guides
and
valveseats
mension
(A)
.
for
wear
before
machining
a
warped
head
.
Always
decarbon-
ize
and
clean
the
head
before
inspectiog
it
.
A
high-quality
Camshaft
straíght
edge
can
be
used
to
check
for
warpage
.
Camshaft
wear
is
usually
caused
by
insufficient
lubrication
.
Visually
inspect
the
cylinder
head
for
cracks
.
If
acracked
Visually
inspect
the
camshaft
lobes
and
journals
for
wear
.
cylinder
head
is
suspected
and
no
cracks
are
detected
Camshaftwear
specifications
are
given
in
Table
b
.
through
the
visual
inspection,
have
the
head
further
tested
for
cracks
byan
authorized
BMW
dealer
.
A
cracked
cylinder
head
Table
b
.
Camshaft
Specifications
must
be
replaced
.
4-cylinder
engines
Axialplay
M42
engine
0
.065-0
.150
mm
(0
.0025-0
.0059
in)
M44
engine
0
.065-0
.150
mm
(0
.0025-0
.0059
in)
Radial
play(Plastigage)
0
.020-0.061
mm
(0
.0008-0
.0024
in)
M42
engine
M44
engine
0
.040-0
.082
mm
(0
.0016-0
.0032
in)
6-cylinder
engines
A
warped
cylinder
head
can
be
machined
provided
no
Axial
pla
y
more
than
0
.3
mm
(0
.012
in)
of
material
is
removed
.
If
further
All
0
.020-0.054
mm
(0
.0008-0
.0021
in)
machining
is
required,
the
head
should
be
replaced
.
Remov-
Radial
play(Plastigage)
0
.150-0.330
mm
(0
.006-0.013
in)
ing
more
than
this
amount
will
reduce
the
size
of
the
combus-
All
tion
chamber
and
adversely
affect
engine
performance
.
A
0
.3
mm
thicker
gasket
is
available
from
an
authorized
BMW
parts
department
for
machined
heads
.
NOTE-
-
On
M44
engines,
check
the
oil
sprayer
tube
in
the
top
Before
machining
the
head
to
correct
for
warpage,
measure
of
the
cylinder
head
coverand
the
tubesea¡
in
the
cyl-
the
total
height(thicknessof
the
cylinder
head)
.
See
Fig
.
9
.
inderhead
.Acloggedsprayertubeoradefectiveseal
Minimum
height
specifications
are
given
in
Table
a
.
will
reduce
oil
flowto
the
camshaft
.
See
Fig
.
10
.
-
If
the
camshaft
is
being
replaced
due
to
cam
lobe
Table
a
.
Cylinder
Head
Height
wear,
the
corresponding
rockerarms
orcam
followers
Engine
New
Minimum
height
shouId
also
be
replaced
to
avofd
damaglng
the
new
(dimension
A)
camshaft
.
CYLINDER
HEAD
AND
VALVETRAIN,
RECONDITIONING
Page 102 of 759
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
.
Page 107 of 759
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
Page 110 of 759
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
.
Page 112 of 759
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
.
Page 125 of 759
GENERAL
.
........
.
...........
.
.
.
.
.
.
.
120-1
Camshaft
Position
(CMP)
Sensor
....
.
.
.
...
120-6
Disabling
Ignition
System
.
.
.
.
.....
.
.
.
.
.
.
.
120-2
Camshaft
position
(CMP)
sensor,
replacing
Warnings
and
Cautions
.
.
.
.
.
.
.....
.
.
.
.
.
.
.
120-2
(4-cylinder
engine)
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
...
120-6
Camshaft
position
(CMP)
sensor,
replacing
IGNITION
SYSTEM
DIAGNOSTICS
.
.
.
.
.
.
120-3
(6-cylinder
engine)
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
120-7
Basic
Troubleshooting
Principles
...
.
.
.
.
.
.
.
120-3
Knock
sensors,
replacing
.
.
...
.
.
.
.
.
.
.
.
.
.
.
.
120-7
Ignition
Firing
Order
.....
.
...
.
.
.
.....
.
.
.
.120-7
IGNITION
SYSTEM
SERVICE
.
.........
.
120-3
Checking
for
Spark
..
.
.
.
.
.
.
.
.
.
.......
.
.
.
120-3
Ignition
coil,
testing
and
replacing
(4-cylinder
engine)
.
.
.
.
.
.
.
.
.
.
.........
.
120-3
Ignition
coil,
testing
and
replacing
(6-cylinder
engine)
.........
.
..........
120-4
Crankshaft
Positionlrpm
Sensor
.......
.
...
120-5
Crankshaft
position/rpm
sensor,
testing
and
replacing
(front
mounted)
.........
.
.
.
.
.
.
120-6
Crankshaft
position/rpm
sensor,replacing
(rear
mounted)
.....
.
.....
.
.....
.
.
.
.
.
.
120-6
GENERAL
Troubleshooting
and
testing
of
the
engine
management
system
should
be
carried
out
using
the
BMW
specialized
ser
This
repair
group
covers
repair
andcomponent
replace-
vice
tester
(scan
tool)
.
ment
information
for
the
ignition
system
.
All
engines
use
a
distributorless
ignition
system
with
indívid-
ual
ignitioncoils
for
each
cylinder
.
There
is
no
distributor
cap
NOTE-
or
ignition
rotor
.
Each
coil
can
be
selectively
controlled
by
the
"
Spark
plug
replacement
is
covered
in
020
Mainte-
engine
control
module
on
a
cylinder-by-cylinder
basis
.
On
later
nance
Program
.
systems,
knock
sensors
are
used
to
monitor
and
control
igni-
"
For
fuel
related
troubleshooting
and
testing,
see
130
tion
knock
(ping)
and
adjusttiming
accordingly
.
Fuel
lnjection
.
Ignition
timing
is
electronically
controlled
and
not
adjust-
All
engines
covered
by
this
manual
use
an
advanced
en-
able
.
The
engine
control
module
(ECM)
usesengine
load,
en-
gine
management
system
.
The
engine
management
system
gine
speed,
coolant
temperature,
and
intake
air
temperature
incorporates
on-board
diagnostics,
fuel
injection,
ignition
and
as
the
basic
inputs
for
timing
control
.
Knock
detection
is
also
other
advanced
engine
control
functions
.
an
input
to
the
control
module,
where
applicable
.
Table
a
.
Engine
Management
System
Variants
Engine
code
1
System
4-cylinder
M42
(1.8
I)
Bosch
DME
Ml
.7
M44
(1
.9
I)
Bosch
DME
M5
.2
(OBD
II)
6-cylinder
M50
1992
(2.5
I)
Bosch
DME
M8
.1
1993-1995
(2
.5
I)
Bosch
DME
M33
.1
M52
1996-1998
(2.8
I)
Siemens
MS
41
.1
(OBD
II)
1998
(2
.5
I)
Siemens
MS
41
.1
(013D
11)
S50US
(3.0
I)
Bosch
DME
M3
.3.1
S52US
(3.2
I)
Siemens
MS
41
.1
(OBD
II)
120
Ignition
System
IGNITION
SYSTEM
120-1
IGNITION
SYSTEM
SCHEMATICS
...
.
.
.
.120-7
TABLES
a
.
Engine
Management
System
Variants
......
120-1
b
.
Ignition
Coil
Resistance
(M42
engine)
......
120-4
c
.
Ignition
Coil
Resistance
(M44
engine)
......
120-4
d
.
Ignition
Coil
Resistance
(6-cylinder
engine)
..
.
.
.
.
.
.
.
.
.
.
.
.....
.
..
120-5
NOTE-
All
engines
coveredby
this
manual,
with
theexception
of
the
1992
M50,
incorporate
knocksensors
as
part
of
the
engine
management
system
.
The
initial
ignition
point
is
determined
by
the
crankshaft
po-
sition/rpm
sensor
during
cranking
.
Once
the
engine
is
run-
ning,
timing
is
continually
adjusted
based
on
operating
conditions
.
A
characteristic
ignition
map
is
shown
in
Fig
.
1
.
A
map
similar
to
the
one
shown
is
digitally
stored
in
the
engine
control
module
.
GENERAL
Page 127 of 759
IGNITION
SYSTEM
DIAGNOSTICS
IGNITION
SYSTEM
SERVICE
Poor
driveability
may
have
a
variety
of
causes
.
The
fault
On
4-cylinder
engines,
an
ignition
coil
pack
is
mounted
to
may
lie
with
the
ignition
system,
the
fuel
system,
parts
of
the
the
passenger
side
strut
tower
in
the
engine
compartment
.
emission
control
system,
or
a
combination
of
the
three
.
Be-
The
coil
pack
integrates
4
individual
coils
.
cause
of
these
interrelated
functions
and
their
effects
oneach
other,
it
is
often
difficult
to
know
where
to
begin
looking
for
On
6-cylinder
engines,
an
ignition
coil
is
located
directly
problems
.
above
each
spark
plug
.
For
this
reason,
effective
troubleshooting
should
alwaysbe-
gin
with
an
interrogation
of
the
On-Board
Diagnostic
(OBD)
system
.
The
OBD
system
detects
certain
emissions-related
engine
management
malfunctions
.
When
faults
are
detected,
the
OBD
system
stores
a
Diagnostic
Trouble
Code
(DTC)
in
the
system
ECM
.
In
addition,
the
Check
Enginewarning
light
will
come
on
if
an
emissions-related
fault
is
detected
.
Two
generations
of
OBD
areusedon
the
cars
coveredby
this
manual
.
See
100
Engine-General
for
OBD
information
.
On-Board
Diagnostics
"
1992-1995
models
............
...
.
..
...
OBD
I
"
1996
and
later
models
.........
.......
..
OBD
II
NOTE-
"
On
carswith
OBD
ti,
specialized
OBD
11
scan
tool
equipment
mustbeused
to
access
DTCs,
either
using
the
BMW
special
tool
or
a
`generic"
OBD
11
scan
tool
.
"
The
OBD
11
fault
memory
(including
an
illuminated
Check
Engine
light)
can
only
be
reset
using
the
spe-
cial
scan
tool
.
Removing
the
connector
from
the
ECM
or
dísconnecting
the
battery
will
not
erase
the
fault
memory
.
Basic
Troubleshooting
Principies
An
engine
that
starts
and
runs
indicates
the
ignition
system
is
fundamentally
working-delivering
voltage
toat
least
some
of
the
sparkplugs
.
A
hard-starting
or
poor-running
engine,
however,
may
indicate
ignition
coil
problems,
cracked
or
dete-
riorated
spark
plug
wires
(4-cylinder
engines
only),
and
worn
or
fouled
spark
plugs
.
WARNING
-
Inefficient
combustion
(richair/fuel
mixture)
can
cause
the
catalytic
converter
to
overheat
and
plug
.
An
overheated
catalytic
converter
can
also
bea
tire
hazard
.
Checking
for
Spark
IGNITION
SYSTEM
120-
3
WARNING
-
If
a
spark
test
is
done
incorrectly,
damage
to
theen-
gine
control
module
(ECM)
or
the
ignitioncoil(s)
may
result
.
Checking
for
spark
is
difficult
onengines
with
distributorless
ignition
systems
.
Try
Rmovng
the
plugs
and
inspecting
for
differences
be-
tween
them
.
A
poor-firing
plug
may
be
wet
with
fuel
and/or
black
and
sooty,
butnot
always
.
If
a
coil
is
not
operating,
the
engine
management
system
will
electrically
disable
the
fuel
injectorto
that
cylinder
.
The
key
is
to
look
for
differences
be-
tween
cylinders
.
Ignition
coil,
testing
and
replacing
(4-cylinder
engine)
1.
Disconnect
mainharness
connector
from
coils
:
"
On
M42
engine,
remove
plastic
covering
from
coils
and
disconnect
individual
harness
connectors
.
"
On
M44
engine,
disconnect
main
harness
connectorat
end
of
coil
pack
.
See
Fig
.
3
.
Fig
.
3
.
Ignition
coil
pack
for
M44
engine
(arrow)
.
Coil
harness
con-
nector
shown
at1
.
IGNITION
SYSTEM
SERVICE