1994 BMW M3 low oil pressure

ignition

Table
b
.
Engine
Management
Systems



engine
has
high
mileage
.

Engine



1
System

4-cylinder
engines
M42
(1992-1995)



Bosch
DME
Ml
.7
M44
(1996-1998)



Bosch
DME
M5
.2
(OBD
II)

6-cylinder
engines
M50
(1992)



Bosch
DME
M3
.1
M50
VANOS
(1993-1995)



Bosch
DME
M3
.3
.1
M52
(1996-1998)



Siemens
MS41
.1
(OBD
II)
S50US
(1995)



Bosch
DME
M3
.3
.1
S52US
(1996-1998)



Siemens
MS41
.1
(OBD
II)

Both
the
4-cylinder
and
6-cylinder
engines
use
a
distributor-

less
ignition
system
with
individual
ignition
coils
for
each
cylin-

der
.

FuelDelivery

Pressurized
fuel
from
the
in-tank
fuel
pump
is
injected
via

solenoid-type
fuel
injectors
.
The
ECM
controls
the
opening

and
closing
of
the
injectors
by
switchingthe
ground
side
of

each
injector
circuit
.
The
exact
amount
of
fuel
injected
is
de-

termined
by
the
amount
of
timethe
injectors
are
open
.

Cooling
System

Whenever
the
engine
is
running,
acoolant
pump
circulates

coolant
through
the
engine
and,
if
either
heater
control
valves

are
open,
through
the
heater
core
in
the
passenger
compart-

ment
.
The
coolant
absorbs
excess
heat
and
carries
it
to
the
ra-

diator
where
it
is
transferred
into
the
passing
airstream
.
A

thermostat
controls
the
flow
of
coolant
through
the
radiator

based
on
engine
temperature
.

Lubrication
System

The
lubrication
system
is
pressurized
whenever
theengine

is
running
.
The
oil
pump
draws
oil
through
a
pickup
in
the
bot-

tom
of
the
oil
pan,thenforces
it
through
a
replaceable
oil
filter

and
finto
the
engine
oíi
passages
.

On
4-cylinder
engines,
the
oil
pump
is
mounted
to
the
front

engine
cover
.
On
6-cylinder
engines,thechain-driven
oil

pump
is
bolted
to
the
bottom
of
the
cylinder
block
.

A
pressure
relief
valve
limits
the
maximum
system
pres-

sure
.
A
bypass
valve
prevents
the
oil
filter
from
bursting
and

insures
engine
lubrication
should
the
filter
become
plugged
.

See
119
Lubrication
System
for
additional
information
.

ENGINE-GENERAL
100-
5

Various
versions
of
DME
systems
are
usedon
thecars
cov-



MECHANICAL
TROUBLESHOOTING
ered
by
this
manual
.
See
Table
b
.
Each
system
is
highly
adaptive
to
compensate
for
things
suchasengine
wear
and



When
troubleshooting
an
engine
that
fails
to
start
or
runs
vacuum
leaks
.



poorly,
first
check
its
mechanical
condition-particularly
if
the

Warnings
and
Cautions

For
personal
safety,
as
well
asthe
protection
of
sensitive
electronic
components,
the
following
warnings
and
cautions
must
be
adhered
to
during
all
troubleshooting,
maintenance,
and
repairwork
.

WARNING
-

"
The
ignition
system
produces
high
voltages
that
can
be
fatal
.
Avoid
contact
with
exposed
termi-
nals
anduse
extreme
caution
when
working
on
a
car
with
the
ignition
switched
on
or
the
engine
running
.

"
Do
not
touch
or
disconnect
any
high
voltage
ca-
bles
from
the
coil,
distributor,
orspark
plugs
while
the
engine
is
running
or
being
cranked
by
the
starter

"
Connect
and
disconnect
the
engine
manage-
ment
system
wiring
and
test
equipment
leads
only
when
the
ignition
is
switched
off
.

"
Gasoline
is
highly
flammable
and
its
vapors
are
explosive
.
Do
not
smoke
or
work
on
a
car
near
heaters
or
other
fire
hazards
when
diagnosing
and
repairing
fuel
system
problems
.
Have
a
fire
extínguisher
available
in
case
of
an
emergency
.

"
Disconnecting
the
battery
may
erase
fault
code(s)
stored
in
control
module
memory
.
Using
special
BMW
diagnosnnc
equipment,
check
for
fault
codes
prior
to
disconnecting
the
battery
cables
.
If
the
Check
Engine
lightis
illuminated,
see
On-

Board
Diagnostics
(OBD)
forfault
code
infor-
mation
.
If
any
other
system
faults
havebeen
de-tected
(indicated
byan
illuminated
warning
light),
see
an
authorized
BMW
dealer
.

CAUTION-

"
Prior
to
disconnecting
the
battery,
read
the
bat-
tery
disconnection
cautions
gíven
at
the
front
of
this
manual
on
page
viii
.

"
Do
notconnect
any
test
equipment
that
delivers
a
12-volt
power
supply
to
terminal15
(+)
of
the
ignition
coil
.
The
current
flow
may
damage
the

ECM
.
In
general,
connect
test
equipment
only
as
specified
by
BMW,
this
manual,
or
the
equip-
ment
maker
.

"
Do
not
disconnect
the
battery
with
the
engine
running
.
Do
notrunthe
engine
with
any
of
the
sparkplug
wires
disconnected
.

MECHANICAL
TROUBLESHOOTING

eiioo4

Fig
.
9
.



Remove
ignition
coils
on
6-cylinder
engine
by
disconnecting
harness
connector
and
removing
mounting
bolts
(arrows)
.

NOTE-

"
The
compression
gauge
reading
shoutd
increase
with
each
compression
stroke
and
reach
near
its
maxi-
mum
reading
in
about
4-6
strokes
.

"All
cylinders
shoutdreach
maximum
compression
in
the
same
number
of
strokes
.
If
a
cylinder
needs
sig-
nificantly
more
strokes
to
reach
maximum
compres-

sion,
there
is
a
problem
.

7
.
Release
the
pressure
at
the
compression
gauge
valve,

then
remove
the
gauge
from
the
spark
plughole
.
Re-

peat
the
test
for
each
of
the
other
cylinders
and
com-

pare
the
results
with
the
values
given
below
.

ENGINE-GENERAL
1
:00-
7

Compression
Pressure

"
Minimum
..........
.
.
..
..
10-11
bar
(142-156
psi)

"
Maximum
difference
between
cylinders
..
.....
.........
0
.5
bar
(7
psi)

Reinstall
the
spark
plugs
and
spark
plug
wires
or
ignition

cofs
.
The
remainder
of
installation
is
the
reverse
of
removal
.
Be
sure
to
reihstall
al¡
wires
disconnected
during
the
test,
especial-

¡y
ground
wires
at
the
coils
and
cylinder
head
cover
(where
ap-
plicable)
.

Tightening
Torque

"
Spark
plug
to
cylinder
head
.......
25
Nm
(18
ft-Ib)

Low
compression
indicates
a
poorly
sealed
combustion

6
.
With
the
parking
brake
set,
the
transmission
in
Park
or



chamber
.
Relatively
even
pressures
that
are
below
specification

Neutral,
and
the
accelerator
pedal
pressed
to
the
floor,



normally
indicate
worn
piston
rings
and/or
cylinder
walls
.
Erratic

crank
the
engine
with
the
starter
.
Record
the
highest



values
tend
to
indicate
valve
leakage
.
Dramatic
differences
be

value
indicated
by
the
gauge
.



tween
cylinders
are
often
the
sign
of
a
failed
head
gasket,

bumed
valve,
or
broken
piston
ring
.

Engine
Mechanical
Troubleshooting
Table

Table
c
lists
the
symptoms
of
common
engine
mechanical

problems,
their
probable
causes
and
the
suggested
corrective

actions
.
The
bold
type
indicates
the
repair
groups
where
appli-

cable
test
and
repair
procedures
can
befound
.

MECHANICAL
TROUBLESHOOTING

100-8
ENGINE-GENERAL

Symptom



1



Probable
cause
and
correctiveaction

1
.
Engine
will
not
start
or
run
.
Starter
cranks



a
.



No
fuel
reaching
engine
.
Check
forfuelin
tank
.

engine
at
normal
speed
.



Fuel
pump
notoperating
.
Repair
Group
160

b
.
No
spark
.
Check
ignition
system
.
Repair
Group
120

c
.
Incorrect
valve
timing
.
Check
timing
chain
.
Repair
Group
117

2
.
Check
Engine
warning
light
illuminated
.



a
.
DME
engine
management
system
self-diagnostic
fault
detected
.
Sea
an
authorized
BMW
dealer
or
other
qualified
shop
for
OBD
II
fault
code
diagnosis
.
See
also
On-
board
Diagnostics(OBD),
given
later
inthis
repair
group
.

3
.
White
exhaust
smoke
(steam)
.



a
.
Failed
cylinder
head
gasket
(probably
accompanied
bylowcompression
readings)
.

Replace
gasket
and
resurface
cylinder
head
if
necessary
.
Repair
Group
113
4
.
Blue-gray
exhaust
smoke
and
oily
spark



a
.
Contaminated
or
gasoline-diluted
engine
oil
.
Change
engine
oil
and
replace
oil
filter
.
plugs
.
Indicates
oii
burning
in
combustion
.



Repair
Group
020

b
.
Faulty
valve
guide
seals
or
valve
guides
.
Replace
valve
guide
oil
seals
or
overhaul
cylinder
head
.
Repair
Group
116

5
.
Pinging
or
rattling
when
under
load,



a
.
Ignition
timing
too
advanced
.
Ignition
knocksensors
faulty
(CheckEngine
light
traveling
uphill,
or
accelerating,
especially



illuminated)
.
Repair
Group
120fromlow
speeds
.
Indicates
pre-ignition
or



b
.
Fuel
octane
leve¡
toolow
.
detonation
.



c
.
Engine
running
too
hot
or
overheating
.
Check
cooling
system
.
Repair
Group
170

6
.
Light
metallic
tapping
that
varies
directly
with
engine
speed
.
Oil
pressure
warning
light
not
illuminated
.

7
.
Light
metallic
knock
that
varies
directly
with
enginespeed
.
Oil
pressure
warning
light
blinking
or
fully
illuminated
;
may
be
most
noticeable
during
hard
stops
or
cornering
.

8
.
Screeching
or
squealing
under
load
that



a
.
Loose,worn,
or
damaged
drive
belt
.
Inspect
belt(s)
.
Repair
Group
020
goesaway
when
coasting
.

9
.
Growling
or
rumbling
that
varieswith
engine



a
.
Remove
drive
belt(s)toidentifyfaulty
component
.
Check
for
play,
bearing
roughness,
rpm
.
Indicates
abad
bearing
or
bushing
in



and
loose
mountings
.
Refer
to
appropriate
repair
group
for
repair
procedures
.
an
engine-driven
accessory
.

DRIVEABILITY
TROUBLESHOOTING



On-Board
Diagnostics
(OBD)

On-Board
Diagnostics
is
incorporated
into
al¡
engine
man-



Two
generations
of
OBD
are
usedon
thecars
covered
by
agement
systems
used
on
the
cars
covered
by
this
manual
.



this
manual
:
Therefore,
checking
for
fault
codes
should
be
the
first
step
in
troubleshootinga
driveability
problem
.
For
additional
informa-



On-Board
Diagnostics
tion
on
engine
management
and
repair
see130
Fuel
Injec-
tion
.



"
1992-1995models
....
.
..
....
.
..
.......
OBD
I

"
1996-1998models
.
....
..
.
.
.
..
.
........
OBD
II

DRIVEABILITY
TROUBLESHOOTING

Tablec
.
Engine
Mechanical
Troubleshooting

b
.
Warped
or
cracked
cylinder
head
.
Resurface
or
replace
cylinder
head
.
Repair
Group
113

c
.
Cracked
cylinder
block
.
Replace
engine
or
short
block
.

c
.
Worn
piston
rings
.
Overhaul
or
replace
engine
.

d
.
Failed
cylinder
head
gasket
.
Replace
gasket
.
Repair
Group
113

d
.
Air/fuel
mixture
too
lean
(Check
Engine
light
illuminated)
.
Repair
Group
130

a
.
Valveclearances
excessive
.
Check
hydraulic
valve
adjusters
.
Repair
Group
116

b
.
Low
oil
pressure
orpossibly
defective
warning
light
circuit
.
Check
oil
pressure
andwarning
light
circuit
.
Repair
Group
119
c
.
Dirty
oil
.
Change
oil
.
Repair
Group
020
.

a
.
Low
oil
leve¡
.
Check
and
correct
oil
leve¡
.

b
.
Low
oil
pressure/worn
or
faulty
oil
pump
.
Oil
pump
pickup
restricted/clogged
.
Check
oil
pressure
.
Repair
Group
119

The
OBD
system
detects
emissions-related
engine
manage-
ment
malfunctions
and
tucos
on
the
Check
Engíne
lightin
the
in-
strument
cluster
.
TheCheck
Engine
light
will
stay
on
until
the
code(s)are
called
up
and
the
memory
is
erased
.
When
faulty
are
detected,
the
OBD
system
stores
a
Diagnostic
Trouble
Code
(DTC)
in
the
system
ECM
.
In
addition,
the
Check
Engine
warn-
ing
light
will
come
on
if
an
emissions-related
fault
is
detected
.

100-
1
4
ENGINE-GENERAL

0013131

Fig
.
13
.
Main
chassis
ground
(arrow)
inleft
front
of
engine
compart-
ment
.

Fuel
Supply

For
the
engine
tostart
and
run
properly,
the
injection
sys-

tem
must
deliver
fuel
in
precise
proportion
to
the
amount
of
air

entering
the
engine
.
Todo
this,
the
injection
system
requires

an
unrestricted
supply
of
fuel
from
the
fuel
pump
.

If
the
fuel
pump
is
not
working,
the
engine
will
notrun
.
If
the
fuel
filter
or
a
fuel
line
is
restricted,
the
engine
may
run
poorly
.
If
the
restriction
is
severe
enough
the
engine
will
not
start
.
lf

fuel
delivery
problemsare
suspected,
perform
the
tests
de-

scribed
in
160
Fuel
Tank
and
Fuel
Pump
.

The
fuel
pressure
created
by
the
fuel
pump
is
controlled
by
a
pressure
regulator
thatreturns
excess
fuelto
the
tank
.
Any
change
in
fuel
pressure
will
cause
a
change
in
the
base
air-fuel

mixture
delivered
to
the
engine
.
If
the
fuel
pressure
is
too
low,
the

base
air-fuel
mixture
will
be
lean
.
lf
the
fuel
pressure
is
too
high,
the
base
mixture
will
be
rich
.
Fuel
pressure
tests
aredescribed
in
160
Fuel
Tank
and
Fuel
Pump
and130
Fuel
Injection
.

NOTE-

Fuel
pressure
tests
require
a
pressure
gauge
.
If
thistoolís
not
avaílable,
the
tests
can
be
performed
byan
authorized
BMW
dealer
or
other
qualified
shop
.

DRIVEABILITY
TROUBLESHOOTING

Properly
operating
fuel
injectors
play
amajor
role
in
fuel
de-

livery
.
The
DMEECM
switches
the
injectors
on
and
off
at
the

negative
(-)
or
ground
side
of
the
connectors
.
Posítíve
(+)
bat-

tery
voltage
is
always
present
at
the
connectors
when
theen-

gine
is
running
.
An
injector
that
fails
or
loses
power
will
not

open,
creating
a
lean
air-fuel
mixture
and
causing
the
engine
to

run
poorly
when
coldor
stumble
on
acceleration
.
An
injector

that
shorts
to
ground
will
remain
open
constantly
when
the
en-

gine
is
running,
creating
a
richair-fuel
mixture
that
can
dilute

engine
oil,
foul
the
spark
plugs,
cause
a
rough
idle,
and
damage

the
catalytic
converter
.

Table
e
lists
additional
symptoms
of
common
engine
drive-

ability
problems,
their
probable
causes,
and
the
suggested

corrective
actions
.
The
entries
in
boldtype
in
the
corrective

action
column
indicate
the
repair
groups
where
applicable
test

and
repair
procedures
can
befound
.

NOTE-

Most
of
the
symptoms
fisted
in
Table
e
will
also
cause
the
Check
Engine
light
to
come
on
.
If
the
light
is
on,

check
for
any
stored
faults
as
the
first
step
ín
trouble-
shooting
driveability
complaints
.

11
.
Detach
wiring
harness
duct
at
rear
bulkhead
panel
and
pull
complete
duct
forward
and
up
to
allow
access
to
rear
of
cylinder
head
cover
.

12
.
Remove
spark
plugs
and
spark
plugwire
loom
.

"
Remove
plastic
cover
from
top
of
cylinder
head
.

"
Disconnect
spark
plug
wires
fromspark
plugs
and
re-

move
spark
plugs
.
"
Unbolt
spark
plug
cable
harness
and
heat
shield
from
right
side
of
cylinder
head
cover
and
set
aside
.

13
.
Unscrew
andremove
cylinder
head
cover
cap
screws

and
remove
cover
.
See
Fig
.
5
.

CAUTION-

Two
of
the
cover
hold-down
screws
are
under
the
spark
plug
cable
duct
.

NOTE-

Make
note
of
the
arrangement
of
cap
screws,
washers
and
rubber
grommets
holding
the
cylinder
head
cover
in
place
.

Fig
.
5
.



Cylinder
head
cover
mounting
points
(arrows)
.

Fig
.
7
.



M44
fuel
rail
air
connection
(A)
and
fuel
supply
and
return
lines
Intake
manifold,
removing



(B)
.

14
.
On
late
engines,
disconnect
injector
air
shrouding
hose

from
fitting
at
center
of
upper
intake
manifold
.



18
.
Disconnect
fuel
supply
and
return
lines
from
fuel
rail
.

15
.
Remove
upper
section
of
intake
manifold
.

"
Disconnect
ali
cables
harness
connectors
from
throttle

housing
and
intake
manifold
.

"
Disconnect
fuel
tank
vent
hose
fromvent
valve
on
low-

er
sitie
of
manifold
.

"
Remove
manifold
support
brackets
.
See
Fig
.
6
.

"
Remove
upper-to-lower
manifold
fasteners
(1
bolt,
2

nuts)
and
separate
upper
manifold
from
lowermani-

fold
.

Note
locating
dowei
sleeves
on
lower
to
upper
manifold
mounting
studs
.
Remove
dowels
and
set
aside
.
See
Fig
.
8
.

CYLINDER
HEAD
REMOVAL
AND
INSTALLATION



113-3

0012686

Fig
.
6
.



Intake
manifold
support
brackets
and
mountinghardware
.
Manifold
for
M44
engine
shows
.

16
.
Disconnect
oil
dipstick
tube
bracket
from
lower
manifold
section
.

17
.
On
M44
engine,
relieve
fuel
pressure
using
com-

pressed
air
(maximum
3
bar
pressure)
at
schroeder

valve
on
fuel
rail
.
Briefly
apply
air
pressure
to
force
fuel

back
intofuel
tank
.
See
Fig
.
7
.

WARNING
-

"
The
fuel
system
retains
fuel
pressure
when
the
engine
is
off
(up
to
75
psi)
.
Use
care
when
dis-
connecting
fuel
lines
.
Unscrew
the
fuel
tank
cap
to
retease
pressure
in
the
tank
.
Wrap
a
clean
shop
towel
around
the
fitting
when
loosening
.

"
Fuel
is
highly
flammable
.
When
working
around
fuel,
do
not
disconnect
any
wires
that
could
cause
electrical
sparks
.
Do
not
smoke
or
worknear
heaters
or
other
tire
hazards
.
Placea
tire
extin-
guisher
in
the
vicinity
of
the
work
area
.

19
.
Disconnect
coolant
hoses
from
vent
valve
on
lower
intake

manifold
.
Remove
crankcase
vent
valve
from
manifold
.

CYLINDER
HEAD,
4-CYLINDER

113-4



CYLINDER
HEAD
REMOVAL
AND
INSTALLATION

20
.
Disconnect
main
engine
wiring
harness
connector
.
La-

bel
and
disconnect
harness
connectors
for
crankshaft

and
camshaft
sensors
.
See
Fig
.
8
.

0012504

Fig
..
Crankcase
vent
valve
(A),
camshaft
and
crankshaft
sensor
harness
connectors
(B),
locating
bushings
(C),
main
engine
wiring
harnessconnector
(D)
.
M44
engine
shown
.

NOTE-

Early
engines
do
not
havea
maín
disconnect
at
the
lower
intake
manifold
harness
.
lf
necessary,
remove
the
cable
ducting
bolts
and
set
harness
ducting
aside
.

21
.
Remové
lower
section
of
intake
manifold
.

"
Remove
Y
shaped
supportbracket
from
underside
of
manifold
.
(See
Fig
.
6
.)
"
Unbolt
support
brackets
from
alternator
and
starter
.
"
Remove
nuts
holding
manifold
to
cylinder
head
and
pull
manifold
back
until
harness
connectors
for
oil

pressure
switch
and
coolant
temperature
sensorare

accessible
.
Label
and
disconnect
connectors,
then
re-

move
manifold
and
set
aside
.

Timing
chains,
uncoupling



26
.
Lock
crankshaft
in
TDC
position
by
insertíng
BMW
spe-

22
.
On
M42
engines,
remove
thermostat
housing
from
up-



cial
tool
no
.
11
2
300
through
bore
and
into
hole
infly-

per
timing
chaincover
.



wheel
or
driveplate
.
See
Fig
.
11
.

23
.
On
late
M44
engines
(January
1997
and
later),
remove



NOTE-
secondary
air
injection
check-valve
from
front
of
engine



"
If
necessary,
remove
plug
from
locating
bore
in
lower
and
lay
aside
.



edge
of
bell
housing
to
insert
locking
tool
.

24
.
Remove
cylinder
identification
sensor
from
upper
tim-
ing
chaincover
.
Remove
upper
timing
chaincover
.
See
Fig
.
9
.

25
.
Set
engine
to
approximate
TDC
by
rotating
in
normal
operating
direction
until
camshaft
lobes
at
cylinder
no
.
1
are
facing
each
other
.
See
Fig
.
10
.

CYLINDER
HEAD,
4-CYLINDER

Fig
.
9
.



Upper
timing
chain
cover
bolts
(arrows)
.
Remove
secondary
air
injection
check
valve
fromhose
(A)
on
M44
engine
.
Re-
move
cylinder
identification
sensor
from
chaincover
(B)
.

0011998

Fig
.
10
.
Engine
set
to
approximate
TDC
.
Cylinder
no
.
1
camshaft
lobes
face
in
and
arrows
on
sprockets
poínt
up
(arrows)
.

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

27
.
Lock
camshafts
at
TDC
by
mounting
BMW
specíal
tool
no
.
113
240
over
square
ends
of
camshafts
.
See
Fig
.
12
.

NOTE-

Check
that
tool
is
squarely
seated
on
cylinder
head
gasket
surface
.
If
necessary,
rotate
camshafts
slightly
using
an
open-end
wrench
at
hex
oncamshafts
.

Fig
.
23
.
When
reinstalling
chain
tensioner
on
M44
engine,
old
oil
in
tensioner
piston
mustbe
expelled
bycompressing
piston
in
vise
.
When
compressing
piston,
only
compress
up
to
end
cir-
clip
(arrow)
.

21
.
Turn
engine
overby
hand
in
direction
of
rotation
at
least

two
fui¡
rotations
.
Reinstall
camshaft
and
crankshaft

locking
tools
to
check
engíne
timing
.
Remove
locking

tools
if
no
faults
are
found
.

22
.
Insta¡¡
upper
timingchain
cover
.

"
Install
gaskets
and
instan
cover
using
two
mounting



Tightening
Torque

bolts
.
Using
a
screwdriver,
lever
down
on
front
cover



"
Cylinder
head
cover
until
cover
gasket
surface
is
flush
with
cylinder
head



to
cylinder
head
(M6
screws)
.......
10
Nm
(89
in-lb)

gasket
surface
.
See
Fig
.
24
.
Tighten
two
bolis
.

"
Insta¡¡
and
tighten
remainder
of
bolis
.

23
.
Install
cylinder
head
cover
.

CYLINDER
HEAD
REMOVAL
AND
INSTALLATION



113-
9

0012507

Fig
.
24
.
Install
upper
timing
case
cover
with
two
bolis,
then
press

down
on
cover
so
that
top
surface
is
flush
withcylinder
head
(arrow)
.
Hold
cover
in
position
and
tighten
bolis
.

"
Clean
old
gasket
glue
from
sealing
surfaces
.
Usea

small
amount
of
3-Bond
®
1209
adhesive
or
equivalent

at
corners
of
half-moon
cut-outs
at
back
of
cylinder

head
.
See
Fig
.
25
.

NOTE-

OnM44
engines,
reptace
sea¡
for
oil
supply
tube
.
See
Fig
.
17
.)

Fig
.
25
.
Rear
of
cylinder
head
cover
showing
area
where
sealant
(ar-
rows)
should
be
applied
.
Inset
shows
cylinder
head
cover
mounting
bolt
and
insulator
assembly
:
M6
screw
(1),
rubber
damper
(2),
washer
(3)
.

24
.
Installation
of
remaining
parts
is
reverseofremoval,

noting
the
following
:

"
Make
sure
al¡
sealing
surfaces
are
clean
and
free
of
old

gasket
material
.
Install
new
intake
manifold
gasket
.

"
On
M44
engine
:
Replace
seals
above
and
below

crankcase
ventvalve
.

"
When
installing
lower
intake
manifold,
make
sure
hol-

low
locating
bushings
are
on
two
lower
studs
.

"
Reinstall
harness
connectors
for
oil
pressure
switch

and
coolant
temperature
sensor
before
installing
in-

take
manifold
.
Tighten
manifold
nuts
in
stages
.

"
Refill
cooling
system
as
described
in
170
Radiator

and
Cooling
System
.

"
Change
engine
oil
and
filter
as
described
in
020
Main-

tenance
Program
.

"
If
necessary,
adjust
accelerator
cable
.

"
Run
engine
at
approx
.
3,500
rpm
for
about
20
seconds

to
allow
hydraulic
chain
tensioner
to
fill
with
oil
.

"
Reconnect
battery
last
.

CYLINDER
HEAD,-CYLINDER

113-12



CYLINDER
HEAD
REMOVAL
AND
INSTALLATION

18
.
Working
from
underside
of
intake
manifold,
disconnect



21
.
Detach
oil
dipstick
guide
tube
from
manifold
.
Disconharness
connectors,
vent
hoses,
and
air
bypass



nectvent
hose
at
base
of
dipstick
.
hoses)
.

22
.
Remove
intake
manifold
from
engine
byremoving
sev-19
.
Working
at
rear
of
intake
manifold,
label
and
disconnect



en
mounting
nuts
from
above
andtwo
support
bracket
fuel
supply
and
fuel
return
lines
.
Remove
fuelline
hold



bolts
from
below
.
See
Fig
.
32
.
down
bracket
to
free
lines
.
See
Fig
.
31
.

NOTE-

On
M52IS52US
engines,
a
special
fitting
is
used
to
re-tain
the
fuel
fines
to
the
fuel
rail
.
Use
BMW
special
tool
no
.
16
1
050
to
expand
the
locking
clip
inside
the
end
of
the
fuellíne
fittings
.

WARNING
-

"
The
fuel
system
is
desígned
to
retan
pressure
even
wheh
the
ignition
is
off
.
When
working
with
the
fuel
system,
loosen
the
fuel
lines
slowly
toal-
low
residual
fuel
pressure
to
dissipate
gradually
.
Avoid
spraying
fuel
.

"
Fuel
is
highly
flammable
.
When
working
around
fuel,
do
not
disconnect
any
wires
that
could
cause
electrfcal
sparks
.
Do
not
smoke
orwork
near
heaters
or
other
fire
hazards
.

"
Always
unscrew
the
fuel
tank
cap
to
release
pres-
sure
in
the
tank
before
working
on
the
tank
or
lines
.

20
.
Remove
mountingscrews
and
release
wiring
harness
duct
at
rear
bulkhead
and
move
aside
.
Remove
wiring
harness
brackets
frombulkhead
.

CYLINDER
HEAD,
6-CYLINDER

Fig
.
32
.
Intake
manifoldnuts
and
support
bracket
bolts
(arrows)
.

CAUTION-

Stuff
clean
rags
into
the
open
intake
ports
topre-
001269s



vent
any
ports
from
falfing
into
the
engine
.
Fig
.
31
.
Fuel
lines
at
intake
manifold
on
M52/S52
engine
.
Use
BMW
special
tool
16
1
050
to
release
locking
fittings
at
ends
of
fuel
enes
.



1



Timing
chains,
uncoupling

23
.
Remove
VANOS
unit
from
frontof
cylinder
head
.
See
VANOS
section
in
117
Camshaft
Timing
Chain
.

24
.
Setengine
to
approximate
TDC
by
rotating
in
normal
operating
direction
until
camshaft
lobes
at
cylinder
no
.
1
are
facing
each
other
.
Arrows
on
camshaft
sprockets
should
be
pointing
up
.

NOTE-

To
confirm
that
the
crankshaft
is
set
to
the
TDC
posi-
tion,
check
that
the
OIT
mark
(0°
TDC)on
the
front
low-
er
timing
chain
cover
ís
aligned
with
the
víbration
damperSee
Fig
.
33
.

25
.
Lock
crankshaft
at
TDC
.

"
Insert
BMW
special
tool
no
.
11
2
300
through
transmis-
sion
bellhousing
and
finto
hole
in
flywheelor
drive
plate
.
See
Fig
.
34
.