1995 BMW M3 head

Mass
air
flow
sensor,
replacing

1
.
Disconnect
harness
connector
and
intake
air
boots

from
air
flow
sensor
.
See
Fig
.
37
.

Fig
.
37
.
Mass
air
flow
sensor
(arrow)
on
M52
engine
.

2
.
Installation
is
reverse
of
removal
.

"
No
adjustment
to
aír
flow
sensor
is
possible
.

"
Check
intake
hoses
for
cracks
and
vacuum
leaks
.

Engine
coolant
temperature(ECT)
sensor,

replacing

The
ECT
sensor
is
a
dual
temperature
sensor
.
One
circuit

provides
coolant
temperature
information
to
the
ECM
while

the
other
circuit
provides
coolant
temperature
information
to

the
instrument
cluster
.

1
.
Remove
left-side
top
engine
cover
.

4
.
Remove
sensor
.

5
.
Installation
is
reverse
of
removal
.

"
Replace
any
lost
coolant
.

0012703

"
Use
a
new
copper
sealing
washer
when
installing
new

Tightening
Torque

"
Engine
coolant
temperature

to
cylinder
head
.....
..
.
...
......
13
Nm
(10
ft-Ib)

FUEL
INJECTION



130-
25

0012704b

Fig
.
38
.
M52
engine
:
Engine
coolant
temperature
(ECT)
sensor
(A)
is
located
beneath
top
engine
cover
(8)
and
crankcase
vent

hose
(C)
.

Intake
air
temperature
(IAT)
sensor,

replacing

The
intake
air
temperature
(IAT)
sensor
for
the
M52/S52US

engine
is
mounted
on
the
bottom
of
the
intake
manifold
.
See
Fig
.

39
.

2
.
Unclip
crankcase
venting
hose
from
cylinder
head
cov-

er
.
See
Fig
.
38
.



Fig
.
39
.
M52/S52US
engine
:
Intake
air
temperaturesensor
location
in

bottom
of
intake
manifold(arrow)
.
Throttle
housing
shown
re

3
.
Under
intake
manifold,
disconnect
harness
connector



moved
.

fromsensor
.

1
.
Disconnect
intake
air
bootfrom
throttle
housing
.
Unbolt

throttle
housing
and
¡ay
aside
.
(It
is
not
necessary
to

disconnect
throttle
cable
or
electrical
harnessconnec-

tors
from
throttle
housing
.)

sensor
.



2
.
Remove
electrical
harness
connector
from
IAT
sensor
.

3
.
Unclip
temperature
sensor
and
remove
from
intake

manifold
.

4
.
Installation
is
reverse
of
removal
.
Use
a
new
gasket
at

the
throttle
housing
.

SIEMENS
MS
41
.1
COMPONENT
REPLACEMENT

130-26



FUEL
INJECTION

Throttle
position
sensor
(TPS),
replacing

The
throttie
position
sensor
is
located
on
the
side
of
the
throttie
housing
.
See
Fig
.
40
.

Fig
.
40
.
M52
engine
:
Throttle
position
sensor
(arrow)
.

1
.
Unplug
harness
connector
from
sensor
.

NOTE
-

On
cars
with
tractioncontrol,
do
not
confuse
the
throttieposition
sensor
on
the
main
throttie
body
wíth
the
throt-
tie
position
switch
on
the
secondary
throttie
body,
where
applicable
.

3
.
Installation
is
reverse
of
removal
.

¡die
speed
control
valve,
replacing

0012700b

The
¡die
speed
control
valve
is
mounted
on
the
underside
of
the
intake
manifoldadjacent
to
the
dipstick
tube
bracket
.
Ac-
cessing
the
valve
is
best
accomplished
by
first
removing
the
throttie
housing
.

1
.
Disconnect
intake
air
bootfrom
throttie
housing
.
Unbolt
throttie
body
and
¡ay
aside
.
(Do
not
disconnect
throttie
cable
or
electrical
harness
connectors
to
throttie
body
.)

2
.
Unbolt
dipstick
tube
bracket
from
intakemanifold
.

3
.
Workíng
under
intake
manifold,
disconnect
electrical
harness
connector
from
¡die
speed
control
valve
.

4
.
Remove
two
bolts
retaining
¡die
speed
control
valve
to
underside
of
intake
manifold
.
Remove
valve
from
intake
manifold
.
Remove
hose
clamp
and
disconnect
hose
.

ECM
PIN
ASSIGNMENTS

mately
one
minute
.

Vacuum
seal

Mounting
bracket

Electrical
connector

0013185

Fig
.
41
.
M52
engine
:
¡die
speed
control
valve
(located
under
intake
manifold)
.

5
.
Installation
ís
reverse
of
removal
.
Use
new
gaskets
when
installing
.

NOTE
-

Poor
driveabilíty
may
be
noticed
atter
installing
a
re-
placement
idle
speed
control
valve
.
After
about
10
min-utes
of
dríving
the
idle
speed
should
return
to
normal
.

ECM
PIN
ASSIGNMENTS

2
.
Remove
twomountingscrews
holding
sensor
to
throttie
housing
.



Engine
control
module
(ECM),
accessing

1
.
Disconnect
negative
(-)
battery
cable
.
Wait
approxi-

CAUTION-

Prior
to
disconnecting
the
battery,
read
the
battery
disconnection
cautions
given
at
the
front
of
this
manual
onpage
vüi
.

2
.
Remove
engine
control
module
(ECM)
compartment
cover
from
right
side
of
engine
compartment
rear
bulk-
head
.
Cover
is
retained
withfour
captíve
screws
.
See
Fig
.
42
.

3
.
Disconnect
control
module
harness
connector
by
re-
leasing
fastener
and
pivoting
connectorup
and
off
ECM
.

4
.
Remove
ECM
from
retaining
brackets
and
pull
ECM
from
its
holder
.

5
.
Installation
is
reverse
of
removal
.

Cooling
System
Pressure
Test



If
the
engine
overheats
and
no
other
cooling
system
testsindicate
trouble,
the
radiator
may
have
some
pluggedpassag-

A
cooling
system
pressure
test
is
used
to
check
for
internal



es
that
are
restricting
coolant
flow
.

leaks
.
Some
of
the
common
sources
ofinternal
leaks
are
a
faulty
cylinder
head
gasket,
a
cracked
cylinder
head,
or
a



Temperature
Gauge
Quick
Check
cracked
cylinder
block
.

The
coolant
temperature
sensor
is
located
on
the
intake
To
doa
cooling
system
pressure
test,
a
special
pressure



manifold
(left)
side
of
the
cylinder
head,
under
the
intake
man-
tester
is
needed
.



ifold
runners
.
See
Fig
.
2
.

WARNING
-

At
normal
operating
temperature
-
the
cooling
sys-
tem
is
pressurized
.
Allow
the
system
to
cool
before
opening
.
Release
the
cap
slowly
to
allow
sale
re-
tease
of
pressure
.

With
the
engine
cold,instan
a
pressure
tester
to
the
expan-

sion
tank
.
Pressurize
thesystem
to
the
specification
listed
be-

low
.
Pressure
should
not
drop
more
than
0
.1
bar
(1
.45
psi)
for

at
leakt
two
minutes
.
If
the
pressure
drops
rapidly
and
there
is
no
sign
of
an
externa¡
leak,
the
cylinder
head
gasket
may
be
faulty
.
Considera
compression
test
as
described
in
100
En-

gine-General
.

The
screw-on
type
expansion
tank
cap
should
also
be
test-

ed
using
a
pressure
tester
and
the
correct
adapter
.

Cooling
System
Test
Pressure

"
Radiator
test
pressure
.........
.
1
.5
bar
(21
.75
psi)

"
Radiator
cap
test
pressure
..
.
........
2
bar
(29
psi)

CA
UTION-

Exceeding
the
speclfied
test
pressure
could
dam-
age
the
radiatoror
other
system
components
.

Carefully
inspect
the
radiator
cap
for
damage
.
Replace
a

faulty
cap
or
a
damaged
cap
gasket
.

Thermostat
Quick
Check



In
later
models,
the
ECT
sensor
and
the
gauge
sender
are
combined
into
one
sender
unit
.
For
wire
colors
refer
to
Table
a
.
To
check
if
the
thermostat
is
opening
and
coolant
is
circulat-

ing
through
the
radiator,
allow
a
cold
engine
to
reach
operat-

ing
temperature
(temperature
gauge
needieapproximately

centered)
.
Shut
off
engine
.
Feel
the
top
radiator
hose
.
If
the

hose
is
hot
to
the
touch,
the
coolant
is
probably
circulating
cor-
rectly
.
If
there
are
any
cool
areas
in
the
hose
or
radiator,
cool-

ant
flow
to
the
radiator
is
probably
restricted
.
Check
for
a
faulty

thermostat
or
aplugged
radiator
.

NOTE-

A
thermostat
that
is
stuck
open
will
cause
the
engine
to
warmup
slowly
and
run
belownormal
temperature
at
highway
speed
.
A
thermostat
that
is
stuck
closed
will
re-

strict
coolant
flow
to
the
radiator
and
cause
overheating
.

RADIATOR
AND
COOLING
SYSTEM



170-
3

U
.¡ig
.v

Fig
.
2
.
Temperature
gauge
sender
on
M44
engine
.
Temperature
gauge
sender
location
is
similar
on
al]
engines
.

In
early
models,
the
engine
coolant
temperature
(ECT)
sen-

sor
for
the
fuel
injection
and
the
coolant
temperature
gauge

sender
are
located
side
by
side
.

Table
a
.
Coolant
Temperature
Sensor
Wire
Colors

Function



Sensor



Terminal



Wire
colors
location
number

Two
sensors
:
Temperature
Rear
1
Brown/violet
gauge
sender



2



Brown/yellow
ECT
sensor



Front



1



Brown/red
2



Brown
or
Brown/black

One
sensor
:
Temperature
Dual
1
Brown/yellow
gauge
sender



sensor



2



Brown/violet
ECT
sensor



3



Brown/red
4
Brown/black
or
Grey/black

TROUBLESHOOTING

Fig
.
13
.
Version
2
auxiliary
fan
mounting
screws
(arrows)
.
Front
bumper
hasbeen
removed
.

4
.
Installation
is
reverse
of
removal
.

Thermostat,
replacing

0013146

The
coolant
thermostat
is
instalied
in
a
housing
at
the
front

of
the
cylinder
head
.
See
Fig
.
14
.

Fig
.
14
.
Coolantthermostat
and
housíng
.

NOTE-

On
M44
engines,
the
thermostat
is
integrated
into
the
thermostat
housíng
.
If
the
thermostat
requiresreplace-
ment,
the
complete
thermostathousing
mustbe
replaced
.

RADIATOR
AND
COOLING
SYSTEM



170-
9

WARNING
-

Allow
the
cooling
system
to
cool
before
opening
ordraining
the
system
.

2
.
Remove
belt-driven
cooling
fan
and
fan
shroudas
de-

scribed
earlier
.

3
.
On
M52/S52US
engines
:
Unclip
wiring
duct
retaining
clips
and
remove
duct
from
above
thermostat
housing
.

Also
remove
engine
front
lifting
bracket
.

4
.
Remove
thermostat
housing
from
front
of
engine
.
See
Fig
.
15
.

Fig
.
15
.
Thermostat
housíng
shown
removed
(6-cylinder
engine)
.

NOTE-

Some
thermostats
have
a
direction
arrowor
venthole
near
the
edge
.
Install
the
thermostat
so
that
either
the
arrow
or
hole
are
at
thetop
.

CAUTION
-

Be
sure
to
reconnect
ground
wire(s)
at
thermostat
housing
mounting
bolt,
where
applicable
.

5
.
Remove
thermostat
.
Note
thermostat
direction
and
ori-

entation
before
removing
.

6
.
Insta¡¡
new
thermostat
and/or
thermostat
housing
using

new
O-ring
and
gasket(s)
as
necessary
.

oo131ss



7
.
Installation
is
reverseof
removal
.
Fill
system
with
cool-

ant
as
described
under
Coolant,draining
and
filling
.

Tightening
Torques

1
.
Drain
radiator
as
described
above
under
Coolant,



"
Thermostat
housing
cover

draining
and
filling
.



to
housing
orcoolant
pump
..
..
....
10
Nm
(89
in-lb)

"
Engine
lifting
bracket
bolt
to
thermostat
housing

(M52/S52US
engine)(M8)
....
..
...
22
Nm
(17
ft-Ib)

COOLING
SYSTEM
SERVICE

170-10



RADIATOR
AND
COOLING
SYSTEM

Coolant
pump,
replacing

The
engine
coolant
pump
is
mounted
in
the
frontof
the
en-

gine
on
the
timing
cover
.
See
Fig
.
16
.

Fig
.
16
.
Coolant
pump
mounted
on
timing
cover
.

NOTE-

Onlyreplacement
coolant
pumps
with
metal
¡mpellers
should
be
installed
.
Pumps
with
plastic
impellers
should
not
be
used
.

1.
Drain
cooling
system
as
described
earlier
.

0013197

WARNING
-

Allow
cool¡ng
system
to
cool
before
open¡ngor
drain¡ng
system
.

2
.
Remove
primary
cooling
fan
shroud
and
cooling
fan
(belt-driven
or
electric)
as
described
earlier
.

Fig
.
17
.
Engine
drive
belt
tensioner
being
released
on
M44
engine
.
Pry
off
tensioner
cover
and
then
lever
tensioner
in
counterciock-
wise
direction
(as
facing
engine)
and
slip
belt
off
pulleys
.

Fig
.
18
.
Drive
belt
tensioner
being
released
on
M52
engine
.
Pry
off
3
.
Disconnect
hoses
from
thermostat
housing
.
Unbolt



tensioner
cover
and
then
lever
tensioner
clockwise
(as
facing
thermostat
housing
from
front
of
cylinder
head
.



engine)torelease
belt
tension
.

4
.
Remove
coolant
pump
drive
belt
.
See
Fig
.
17
or
Fig
.
18
.

NOTE-

-
Mark
direction
of
drive
belt
rotation
if
reusing
belt
.



"
The
6-cylinder
coolant
pump
¡s
mounted
on
studs
and
retained
by
nuts
.
"
Severa¡
drive
belt
and
tensioner
configurations
havebeenused
in
E36
models
.
Refer
to
020
Maintenance
Program
and
640
Heating
and
Air
Conditioning
.

5
.
Remove
coolant
pump
pulley
from
pump
.

6
.
Remove
mounting
fasteners
from
pump
.

COOLING
SYSTEM
SERVICE

NOTE-

"
The
4-cylinder
coolant
pump
¡s
mounted
us¡ng
two
dif-
terent
length
bolts
.
Note
where
thelonger
bolt
fits
dur-
ing
disassembly
.

0011989

7
.
Insert
twoscrews
(M6)
in
tapped
bores
and
tighten
uni-
formly
until
pump
is
free
from
timing
chain
cover
.
See
Fig
.
19
.

Dimension
A=15mm
(0
.60
in
.)

Fig
.
9
.



Preload
rear
clamping
bracket
as
specifíed
tohelp
prevent
system
rattling
.

Exhaust
manifolds,
removing
and

installing

WARNING
-

Do
not
work
under
a
lifted
car
unfess
itis
solidly
supportedonjackstands
designed
for
that
pur-
pose
.
Never
work
underacar
that
is
supported
solely
by
ajack
.

EXHAUST
SYSTEM



180-
5

2
.
On
1996
and
later
6-cylinder
engines,
disconnect
the
secondary
air
check
valve
and
eipe
from
the
exhaust
manifold
.

3
.
Unbolt
front
exhaust
pipe(s)
from
exhaust
manifold(s)
.

4
.
Remove
exhaustsupport
bracket
from
transmission
.

5
.
Loosen
andremove
nuts
fromexhaust
manifolds
and
remove
manifolds
.
Discard
nuts
and
gaskets
.

NOTE-

On
cars
wíth
oxygen
sensors
mounted
in
the
exhaust
manifolds,
usecare
when
removing
manifolds
.
Tobe
safe,
remove
the
sensors
from
the
manifolds
before
re-
moving
manifolds
.

6
.
Installation
is
reverse
of
removal
.

"
Coatexhaust
manifold
mounting
studs
with
copper
paste
before
installing
new
nuts
.
"
Insta¡¡
manifold
gaskets
with
arched
side
facing
mani-
folds
.

Always
use
new
retaining
nuts
and
gaskets
when
removing



Tightening
Torques

and
installing
the
exhaust
manifolds
.



"
Exhaust
manifold
to
cylinder
head

4-cylinder
engine
(M7
nut)
........
15
Nm
(11
ft-Ib)

1
.
With
exhaust
system
cold,raise
and
support
car
for
ac-



6-cylinder
engine
(M7
nut)
........
20
Nm
(15
ft-Ib)
cess
lo
exhaust
system
.

EXHAUST
SYSTEM
REPLACEMENT

GENERAL
..
.
.
.
.
.
.
.
.
.
.
.
.
.
......
.
......
210-1



CLUTCH
MECHANICAL
.
.
.
.
.
...
.
.....
.
.
210-3

CLUTCH
HYDRAULICS
.
.
.
.............
210-1



Clutch,
removing
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
...
.
.
.
.
210-4

Clutch,inspecting
and
installing
.
.
.
.
.
.
.
.
.
.
.
.210-5Clutch
hydraulic
system,



Transmission
pilot
bearing,replacing
.
.
.
.
...
210-6
bleeding
and
flushing
.
.
.
.
.
.......
.
.....
210-2

Clutch
master
cylinder,
replacing
..
.
.
.
.
.
...
210-2



Table

Clutch
slave
cylinder,
replacing
...
.
.
.
.
.
.
.
.
210-3



a
.
Clutch
Disc
Diameter
.............
..
..
.
......
210-3

GENERAL



CLUTCH
HYDRAULICS

This
repair
group
covers
replacement
of
the
clutch
mechan-



The
Clutch
is
hydraulically
actuated
by
the
master
and
slave
¡cal
and
hydraulic
components
.
Special
tools
may
be
required



cylinders
.
Clutch
disc
wear
is
automatically
taken
upby
the
for
some
of
the
procedures
.
Read
the
procedure
through
be-



pushrod
travelof
the
slave
cylinder,
making
periodic
adjust-fore
beginning
a
job
.



ments
unnecessary
.

NOTE-

See200
Transmission-General
for
transmission
applicatíon
information
.

The
major
components
of
the
clutch
system
are
shown
in

Fig
.
1
.

Engine



Pressure
plate

flywheel,,
assembly

Clutch

Flywheel
bolt

Pressure
plate
release
lever



Release
lever

Fig
.
1
.



Clutch
assembly
and
hydraufcs
.

210
Clutch

Release
bearing

Pushrod

A
soft
or
spongy
feel
to
the
clutchpedal,
long
pedal
free-
play,
or
grinding
noises
from
thegears
while
shifting
can
all
in-
dicate
problems
with
the
Clutch
hydraulics
.
In
these
circum-
stances
it
is
best
to
start
with
a
clutch
fluid
flush,
followed,
if

necessary,
byreplacement
of
the
hydraulic
parts
.

From
brake
fluid
reservoir

CLUTCH
210-1

0

0

Transmission
inputshaft

Clutch
master
cylinder

Bulkhead

Slave
cylinder
6535

CLUTCH
HYDRAULICS

Fig
.
3
.



Clutch
master
cylinder
mounting
bolts
.

Clutch
slave
cylinder,
replacing

0012589

Tightening
Torques

"
Clutch
master
cylinder
to
bulkhead
..
22
Nm
(17
ft-Ib)
"
Fluid
line
to
master
cylinder

orslave
cylinder
.................
16
Nm
(12
ft-1b)

The
clutch
slave
cylinder
is
mounted
on
the
left
side
of
the

transmission
.



CLUTCH
MECHANICAL

1
.
Remove
brake
fluid
reservoir
cap
.
Using
a
clean
sy-

ringe,
remove
brake
fluid
from
reservoir
.

2
.
Disconnect
fluid
hose
from
slave
cylinder
.
Place
a
pan

under
hose
to
catch
any
excess
fluid
.

3
.
Unbolt
slave
cylinder
from
transmission
.
See
Fig
.
4
.

4
.
Installation
is
reverse
of
removal,
noting
the
following
:

"
Check
for
wear
on
pushrod
.
Any
other
wear
except
on

tipis
caused
by
misalignment
of
clutch
components
.

"
Lightly
coat
pushrod
tip
with
molybdenum
disulfide

grease
(Molykote
0
Longterm
2
or
equivalent)
.

"
During
installation
be
sure
pushrod
tip
engages
recess

in
clutch
release
lever
.

"
Fill
fluid
reservoir
with
clean
fluid
.

"
Bleed
clutch
hydraulics
as
described
earlier
.

CLUTCH
210-
3

Fig
.
4
.



Clutch
slave
cylinder
mounting
bolts
(arrows)
.

Tablea
.
ClutchDisc
Diameter

Model



Diameter

3181/is/iC



215
mm
(8
.46
in)

325i/is/iC



228
mm
(8
.98
in)
323is/iC

328i/is/iC



240
mm
(9
.45
in)
M3

0012715

Tightening
Torques

"
Clutch
slave
cylinder

to
transmission
.
.
................
22
Nm
(17
ft
lb)
"
Fluid
line
to
slave
cylinder
......
.17
Nm
(10-12
ft
lb)

The
transmission
must
be
removed
from
the
engine
to
ac-

cess
the
clutch
mechanical
components
.
It
is
recommended

that
the
clutch
disc,
pressure
plate
and
release
bearing
be
re-

placed
duringa
clutch
overhaul
.
Be
sure
to
check
the
bottom

of
the
bellhousing
for
oil
.
If
engine
oil
is
found,
check
for
a

faulty
rear
crankshaft
oil
seal
.

CLUTCH
MECHANICAL