1997 BMW 328i section 5

Foreword

This
service
manual
covers
1992
through
1998
BMW
3
Series
models,
and
is
specifically
de-
signed
to
cover
only
those
models
built
for
sale
in
the
United
States
.

BMW,
and
most
accessories
and
parts
sellers
specializing
in
BMWs,
refer
to
the
3
Seriescars

coveredby
this
manual
as
the
E36
model
.
The
code
"E36"
is
BMW's
internal
code
for
the
basic
plat-

form
sharedby
al¡
of
the
cars
coveredby
this
manual
.
Except
for
the
engine
and
a
few
other
compo-

nents,
the
models
coveredby
this
manual
share
many
of
same
components
suchas
suspension

parts,
body
panels,
and
the
interior
pieces
.
When
ordering
parts,
especially
body
parts,
knowing
the

E36
code
may
be
helpful
.

BMW
also
usesan
interna¡
code
for
the
enginesused
in
the
3
Series
models
.
Consult
the
text
in

the
100
Engine-General
repair
group
ofthis
manual
for
a
complete
listing
of
engine
codes
.
Engine
-

code
information
is
primarily
used
internally
by
BMW,
but
may
be
helpful
if
you
haveaccess
to
BMW

technical
information
.

Forthe
BMW
ownerwith
basic
mechanical
skills,
this
manual
gives
detailed
maintenance
and
re-

pair
information
.
In
addition,
the
BMW
owner
who
hasno
intention
of
working
on
his
or
her
own
car

will
findthat
owning
and
reading
this
manual
will
make
it
possibleto
be
better
informed
and
todis-

cuss
repairs
more
intelligently
with
a
professional
technician
.
This
manual
has
been
prepared
from

the
repair
information
that
BMW
provides
to
its
factory-trained
technicians
and
has
been
developed

primarily
with
the
do-it-yourself
BMW
owner
in
mind
.
The
aim
throughout
has
been
clarity
and
un-

derstanding
with
practical
descriptions,
step-by-step
procedures,
and
accurate
specifications
.

The
BMW
owner
intending
to
do
maintenance
and
repair
should
have
a
set
of
tools
including
a
set

of
metric
wrenches
and
sockets,
screwdrivers,
a
torque
wrench,
and
feeler
gauges,
since
these
ba-

sic
tools
will
beused
to
do
the
majority
of
the
maintenance
and
repair
procedures
described
in
this

manual
.
This
manual
includes
detailed
information
onthese
basic
tools
and
other
tips
for
the
begin-

ner
in
the
first
section
of
the
manual,
entitled
010
Fundamentals
for
the
Do-It-Yourself
Owner
.

For
some
of
the
repairs
described
in
this
manual,
BMW
technicians
use
special
tools
.
The
text
will

note
when
a
repair
requires
these
special
tools
and,
where
possible,
will
recommend
practica¡
alter-

natives
.

GENERAL

FUNDAMENTALS
FORTHE
DO-IT
YOURSELF
OWNER



010-1

010
Fundamentals
for
the

Do-lt-Yourself
Owner

GENERAL
.......
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.010-1



TOOLS
.
.
...
.
............
.
............
010-8

Basic
Tool
Requirements
......
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.
010-8
HOW
TO
USE
THIS
MANUAL
.
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010-2



JackStands
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010-9

Warnings,
Cautions
and
Notes
.........
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.
010-2



Oil
Change
Equipment
.
....
.
......
.
...
.
.
010-9

GETTING
STARTED
.
.......
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.010-2



Torque
Wrench
....
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.
..
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...
.
010-10

Feeler
Gauges
.
...
.
.
.
.......
.
.
.
.
.
.
.
.
.
010-10
Safety



....
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.....



.....
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010-2



Digital
Multimeter



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010-10
Lífting
the
Car
...........
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010-3



gMW
Special
Tools
...
.
....
..
.....
.
...
.
010-11
Raising
car
safely
...
..
...
.



...
.
.....
.
...
010-3

Working
under
car
safely
...
..
....
.
.....
.
...
010-4



EMERGENCIES
.
.
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.
010-11

ADVICE
FOR
THE
BEGINNER
.......
.
.
.
010-4



Changing
a
Tire
.
.
.
.
.
.
....
..
.
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.
.
.
.
.010-11
Car
Will
Not
Start
....
.
....
.
.
.
........
.010-11
Planning
Ahead
....
.
...........
.
....
.
.
.
010-4



Jump
Starting
Car
..
.
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.
....
.
...........
010-12
Cleanliness
.
.
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..
....
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.
010-4



Overheating



.
.....
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...
.
010-12
Non-reusable
Fasteners
...
.
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.
.
.
010-5



Low
Oil
Pressure
...
...
.
.
...
.
.
.
..
...
....
010-13
Tightening
Fasteners
.....
.
.
.
...
.
.
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.
.
010-5



Brake
Fluid
Level



.
.
.....
.
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.
...
.
.....
010-13
Gaskets
and
Seals
.......
.
.
.
...
.
.....
.
.
.
010-5



Check
Engine
Warning
Light
.
.
.
...
.
.....
010-13
Electrical
Testing
.
.
.
.
.
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.
...
.
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.
010-6



pim
Lights
.....
.
..
.
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....
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.........
010-13Wire
Repairs



.
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...
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......
010-6



Towíng



.
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...
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.010-13

BUYINGPARTS



.
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.
010-6



Spare
Parts
Kit
.
.
.
.
.
.
.......
.
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.
.
.
.....
010-14

Genuine
BMW
Parts
.
.
.
.
.
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.
.
.
.
......
010-6

Non-returnable
Parts
.
.
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.
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.
.
......
010-7



TABLES

Information
You
Need
to
Know
.
.
.
.
.
.
......
010-7



a
.
General
Bolt
Tightening
Torques

SERVICE
.
.
.
.
.
.
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.
.
.
.
.
.......
.
..........
010-7

Although
the
BMW
is
a
sophisticated
and
complex
machine,

basic
maintenance
can
be
accomplished
byan
interested
own-

er
with
mechanical
skills
and
the
right
information
.
Most
of
the

preventive
maintenance
that
is
required
in
the
lifetime
of
theav-

erage
BMW
is
weil
within
the
capabilitiesof
the
do-it-yourseifer
.

WARNING
-

Do
not
use
this
manual
unless
you
are
familiar
with

basicautomotive
repair
procedures
and
sale
work-
shop
practices
.
This
manual
illustrates
the
work-
shop
procedures
required
for
most
service
work
;it

is
not
a
substitute
for
full
and
up-to-date
information

from
the
vehicle
manufacturer
or
for
proper
training

asan
automotive
technician
.
Note
that
it
is
not
pos-

sible
for
us
to
anticipate
al¡
of
the
ways
orconditions
underwhich
vehicles
may
be
serviced
or
to
provide

cautions
as
to
all
of
the
possible
hazards
that
may

result
'

in
Nm
(max
.
permissible)
.
..
.
...
............
.
010-5

WARNING
-

Your
common
sense
and
good
judgment
are
crucial
tosale
and
successful
service
work
.
Read
proce-
dures
through
before
starting
them
.
Thinkabout
whether
the
condition
ofyour
car,
your
leve¡
of
me-

chanical
skill,
or
your
leve¡
of
reading
comprehen-
sion
might
result
in
orcontribute
in
some
way
to
an
occurrence
that
might
cause
you
injury
damage
your
car,
or
result
in
an
unsafe
repair
.
lf
you
havedoubts
for
these
or
other
reasonsaboutyour
abilíty
to
perform
sale
repair
work
onyour
car,
have
the

work
done
at
an
authorized
BMW
dealer
or
other
qualified
shop
.

This
section
of
the
manual
is
intended
to
helpthe
beginner

get
started
.
To
begin
with
there
is
a
discussion
on
How
To
Use

This
Manual
.
Tips
on
mechanicas
skills
and
workshop
practic-

es
that
can
help
the
beginner
do
a
faster
and
more
thorough
job

can
be
foundunderGettingStarted
.
The
basic
tools
needed

to
do
most
of
the
procedures
in
this
manual
are
foundunder
Tools
.
The
section
ends
with
a
quick
reference
guide
to
Emer-
gencies,
including
basictroubleshooting
and
information
on
how
to
gauge
the
seriousness
of
a
problem
.

GENERAL

010-2



FUNDAMENTALS
FOR
THE
DO-ITYOURSELF
OWNER

HOW
TO
USE
THIS
MANUAL

A
note
contains
helpfulinformation,
tipsthat
will
hefp
in
The
manual
is
divided
into
ninesections
:



doinga
better
job
and
completing
!t
more
easíly
.

0
GENERAL
DATA
AND
MAINTENANCE

1
ENGINE

2
TRANSMISSION

3
SUSPENSION,
STEERING
AND
BRAKES

4
BODY

5
BODY
EQUIPMENT

6
ELECTRICAL
SYSTEM

7
EQUIPMENTANDACCESSORIES

ELECTRICAL
WIRING
DIAGRAMS

0
GENERAL
DATA
AND
MAINTENANCE
coversthe
rec-

ommended
maintenance
schedules
and
service
procedures

needed
to
perform
BMW
scheduled
maintenance
work
.
Also

within
this
section
is
the
010
Fundamentals
for
the
Do-It-

Yourself
Owner
section,
which
contains
basic
instructions,
tips
and
helpful
hints
for
do-it-yourself
maintenance
and
repair
.

The
next
seven
sections
(1
through
7)
are
repair
based
and

are
further
broken
down
into
three
digit
repair
groups
.
Each
ma-

jor
section
begins
with
a
General
repair
group,
e
.g
.
100En-

gine-General
.
These
"00"
(doublezero)
groups
aremostly

descriptive
in
nature,
covering
topics
suchas
theory
of
opera-
tion
and
troubleshooting
.
The
remainder
of
the
repair
groups

contain
the
more
involved
repair
information
.
The
last
major

section
contains
detailed
electrical
wiring
diagram
schematics
.

A
master
listing
of
the
9major
sections
and
the
correspond-
ing
individual
repair
groups
can
befoundon
the
inside
front
cover
.

Each
repair
group
begins
with
a
Table
of
Contents
listing
the

majos
subject
headings
within
the
group
.
Page
numbers

throughout
the
manual
are
organizedaccording
to
the
repair
groupsystem
.
For
example,
youcan
expect
tofind
repair
infor-
mation
on
brakes
(Repair
Group
340)
beginning
on
page
340-
1
.
A
comprehensive
index
can
be
found
at
the
back
of
the
man-

ual
.

Warnings,
Cautions
and
Notes
Throughout
this
manualare
many
passages
with
the
head-
ings
WARNING,
CAUTION,
or
NOTE
.
These
very
important
headings
have
diflerent
meanings
.

WARNING
-

The
text
under
this
heading
warns
of
unsafe
practic-
es
thatare
very
likelyto
cause
ínjury,
eitherby
dírect
threat
to
the
person(s)
pertorming
the
work
or
by
in-
creased
risk
of
accident
or
mechanfcal
fallure
whíle
driving
.

CAUTION-

A
caution
calls
attention
to
important
precautions
to
beobserved
during
the
repair
work
that
will
helo
prevent
accidentally
damaging
the
caror
its
parts
.

GETTING
STARTED

Safety

NOTE-

Please
read
every
WARNING,
CAUTION,
and
NOTE
at
the

front
of
the
manual
and
as
they
appear
in
repair
procedures
.

They
are
very
important
.
Read
them
before
you
begin
any

maintenance
or
repair
job
.

Some
WARNINGs
and
CAUTIONs
are
repeated
wherever

they
apply
.
Read
them
all
.
Do
not
skip
any
.
These
messages
are
important,
even
to
the
owner
who
never
intends
to
workon

thecar
.

GETTING
STARTED

Most
of
the
necessary
maintenance
and
minor
repair
that
an

automobile
will
need
canbe
done
with
ordinary
tools,
evenby

owners
with
little
or
no
experience
in
car
repair
.
Below
is
some

important
information
on
how
to
work
safely,
a
discussion
of

what
tools
will
be
needed
and
how
to
use
them
.

Although
an
automobile
presents
many
hazards,
common

sense
and
good
equipment
can
helo
ensure
safety
.
Many
acci-

dents
happen
because
of
carelessness
.
Pay
attention
and
stick
to
these
few
important
safety
rules
.

WARNING
-

"
Never
run
the
engine
in
the
work
area
unless
it
is
well-ventflated
.
Theexhaustshouldbe
vented
to
the
outside
.
Carbon
monoxide
(CO)
in
theex-
haust
kilts
.

"
Remove
all
neckties,
scarts,
loose
clothing,
or
jewelry
when
working
near
running
engines
or
power
tools
.
Tuck
in
shirts
.
Tie
long
haír
and
se-
cure
it
under
a
cap
.
Severe
injury
can
result
from
these
things
beíngcaught
in
rotating
parts
.

"
Remove
ríngs,
watches,
and
bracelets
.
Asíde
from
the
dangersof
moving
parts,
metallic
jew-
elry
conducts
electricity
and
may
cause
shorts,
sparks,
bums,
or
damage
to
the
electrical
sys-
tem
when
accidentally
contacting
the
battery
or
other
electrical
terminals
.

"
Disconnect
the
battery
negative
()
cable
when-
ever
working
on
ornear
the
fuel
system
or
any-
thlng
that
is
electrically
powered
.
Accidental
electrícal
contact
may
damage
the
electrical
system
or
cause
a
fire
.

020-2



MAINTENANCE
PROGRAM

GENERAL

The
information
given
in
this
repair
group
includes
the
routine

checks
and
maintenance
steps
that
are
both
required
by
BMW

under
the
terms
of
the
vehicle
warranty
protection
and
recom-

mended
by
BMW
to
ensure
long
and
reliable
vehicle
operation
.

GENERAL

NOTE-

Aside
from
keeping
yourcar
in
the
bestpossible
condi-
tion,
proper
maintenance
plays
a
role
in
maintaining
full
protection
under
BMWs
new-car
warranty
coverage
.
If
in
doubtabout
the
terms
and
conditions
of
yourcark
warranty,
an
authorized
BMW
dealer
should
be
able
to
explain
them
.

NOTE-

BMW
is
constantly
updating
their
recommended
main-
tenance
procedures
and
requirements
.
The
informa-
tion
contained
here
is
as
accurate
as
possible
at
the
time
of
publication
.
If
hhere
is
any
doubt
aboutwhat
pro-
cedures
apply
to
a
specific
model
or
model
year,
or
what
intervals
should
be
followed,
remember
that
an
authorized
BMW
dealer
has
the
latest
information
on
factory-recommended
maintenance
.

BMW
Service
Indicator

The
BMW
Service
Indicator
notifies
the
driver
when
mainte-
nance
is
required
.
The
service
indicator
consístsof
multiple
light
emitting
diodes
(lEDs)-typically
five
green,
one
yellow,
andone
red-as
well
as
OIL
SERVICE
and
INSPECTION
indi-
cators
.

When
the
ignition
is
tumed
on,the
green
LEDs
come
on
.
They
go
out
when
the
engine
is
started
.
After
the
Service
Indi-
cator
is
reset,
al¡
green
LEDs
will
be
illuminatedwith
the
keyon
.
As
thecar
is
driven
in
normal
use,
fewer
and
fewer
green
LEDs
will
be
illuminated
before
start-up,indicating
that
the
next
main-
tenance
interval
is
approaching
.

When
thecar
has
accumulated
sufficient
use
to
require
the
next
maintenance
interval,
the
yellow
LED
will
come
on
along
with
either
the
OIL
SERVICE
indicator
or
the
INSPECTION
in-
dicator
.
These
LEDs
will
stay
on
after
the
engine
is
started
.
If
maintenance
service
is
delayed,
thered
LED
will
also
illuminate
as
a
reminder
that
maintenance
service
is
overdue
.

An
OIL
SERVICE
interval
will
alwaysbe
followed
by
an
IN-
SPECTION
interval,
which
will
then
be
followed
byan
OIL
SER-VICE
interval,
andsoon
.
See
Fig
.
1
.

'
80
100/

60
II

"
1

,



ló
1
,
4
`20
140s



#
X120
100
leo
A
O
,



80



km/h`F



*101
200
,
,
~60

BMW
has
taken
a
unique
approach
to
establishing
mainte-

nance
intervals
.
BMW's
Service
Indicator
System
computes

maintenance
intervais
based
not
only
on
elapsed
mileage,
but



Fig
.
1
.



Service
indicator
display
in
lower
section
of
speedometer
.
also
on
such
inputs
as
enginespeed,engine
temperature,
number
of
starts,
and
length
oftrips
.
At
the
appropriate
time,
the
system
indicates,
through
lights
in
the
instrument
cluster,
when



Oil
Service

the
next
routine
maintenance
is
due
.

The
Oil
Service
indicator
signals
the
need
for
the
most
basic
levelof
routine
maintenance
.
BMW's
required
oil
service
speci-
fies
changing
the
engine
lubricating
oil
and
the
engine
oil
filter

after
the
engine
has
been
warmed
up
.
BMW-recommended
ad-

ditional
maintenance
for
this
service
is
listed
in
Table
a
.

NOTE-

For
reference,
the
BMW
Oil
Service
requirements
are
approximately
equivalent
to
the
maintenance
that
other
European
manufacturers
specify
at
intervals
with
a
maximum
of
every
7,500
miles
or6
months
.

CAUTION-

Be
sure
to
follow
the
ínstructions
forresetting
the
Oil
Service
indicator
fight
.
The
Inspection
indica-
tor
can
be
accidentally
reset
rendering
its
function
inaccurate
.

Inspection
l
and
Inspection
II

The
Inspection
indicator
signals
the
need
for
more
compre-
hensive
maintenance
and
Inspection
.
There
are
two
sets
of
in-
spection
requirements,
Inspection
I
and
Inspection
ll
.
These
inspections
alternate
throughout
a
car's
maintenance
history
.
If
the
last
Inspection
interval
was
Inspection
I,
the
next
Inspection
interval
(following
an
Oil
Service)
will
be
Inspection
ll,
the
next
after
that
will
be
Inspection
I,
and
so
on
.

Inspection
I
tasks
are
listed
in
Table
b
.
Inspection
II
in-
cludes
most
of
the
tasks
from
Inspection
I
with
additional
In-
spection
11
tasks
.
A
complete
listing
of
Inspection
II
tasks
are
listed
in
Table
c
.

Air
filter,
replacing



Spark
plugs,
replacing

The
specified
maintenance
intervals
for
the
air
filter
are



To
access
the
spark
plugs
on
4-cylinder
engines,
remove
the

based
on
normal
use
.
If
thecar
is
operated
primarily
in
dusty



cover
fromatop
the
sparkplugs
.
See
Fig
.
10
.
Using
the
special

conditions,
the
air
filter
should
be
serviced
more
frequently
.



spark
plug
wire
removal
tool
(attached
to
rear
of
cylinder
head

beneath
engine
cover),
gently
pull
the
spark
plugwire
from
the

To
replace
the
air
filter
on
6-cylinder
engines,
unclip
and
sude



spark
plug
.
See
Fig
.
11
.
Blow
away
any
dirt
from
around
the
the
filter
cartridge
assembly
out
of
the
air
boxand
remove
the



base
of
the
plug
to
prevent
it
from
entering
theengine
.
Remove

filter
from
the
frame
assembly
.
See
Fig
.
8
.



and
install
the
spark
plugs
one
at
a
time
.

0012625

Fig
.
8
.



To
remove
air
filter
cartridge
on
6-cylinder
engines,release
fil-
ter
cartridge
at
sides
(arrows)
and
then
remove
filter
element
insert
from
cartridge
.

To
replace
the
air
filter
elementon
4-cylinder
engines,
sepa-

rate
the
upper
air
filter
housing
section
from
the
lower
section
by

unfastening
the
spring
clips
.
Remove
the
air
filter
element
from

the
air
filter
housing
.
See
Fig
.
9
.
Wipe
the
inside
of
the
air
filter

housing
clean
and
install
the
new
element
.
Reinstall
the
upper

air
filter
housing,
making
sure
that
the
two
halves
are
mated

correctly
.
Refasten
the
spring-clips
.

Fig
.
9
.



Air
filter
element
being
removed
on
4-cylinder
engine
.

MAINTENANCE
PROGRAM



020-
11

NOTE-

Spark
plug
applications
are
often
updated
and
super-
seded
from
the
original
plug
specification
.
Consuff
an
authorized
BMW
parts
department
for
the
latest
parts
_'
information
.
The
sparkplug
fisted
in
the
owners
manu-
al
may
not
be
the
latest
recommend
spark
plug,
espgp
cially
on
older
cars
.

0012631

Fig
.
10
.
To
remove
engine
cover
above
sparkpiugs
on
4-cylinder
en-
gine,
turnretainers
90°
counterclockwise
and
lift
cover
off
.

0012630

Fig
.
11
.
To
remove
spark
plugwirefrom
spark
plug
on
4-cylinder
en-

gine,
sude
special
removal
tool
over
spark
plug
wire
end
(ar-

row)
and
pull
straightoff
.
Usea
screwdriver
for
added

leverage
.
Special
tool
is
stored
at
rear
of
cylinder
head
below

top
cover
.

ENGINE
COMPARTMENT
MAINTENANCE

Accelerator
and
Throttle
Linkage

The
accelerator
and
throttie
linkage
should
be
lubricated
pe-
riodically
.
Use
a
general
purpose
oil
on
the
joints
and
bearings

of
the
linkage
.
Use
a
multipurpose
grease
on
the
bearing
points

of
the
throttie
plate
.

Engine
Drive
Belts

Drive
belts
and
pulleys
transfer
power
from
theengine
crank-

shaft
to
various
accessories
.
See
Fig
.
13
.
Depending
on
model

and
model
year,
engine
driven
accessories
are
driven
by
V-

belts,
poly-ribbed
(serpentine)
belts,
or
a
combination
of
the

two
.
For
example,
early
4-cylinder
engines,
usetwo
V-belts
and
one
poly-ribbed
belt
.

Inspect
drivebelts
with
the
engine
off
.
lf
the
belt
shows
signs

of
wear,
cracking,
glazing,
or
missing
sections,
it
should
be
re-

placed
immediately
.

V
belt,
replacing

(4-cylinder
engines
built
up
to
1194)

0012472

Fig
.
13
.
Drive
belt
and
tensioner
assembly
for
late
4-cylinder
engine
wíth
poly-ribbed
drive
belt
.

V-belts
should
be
inspected
during
regular
maintenance
in-

tervais
.
Incorrect
tension
can
decrease
the
life
of
the
belt
and

the
component
it
drives
.
The
V-belt
tension
is
adjusted
through

a
toothed-rack
mechanism
.

Inspect
belts
with
the
engine
off
.
Twist
the
beltto
inspect
its

sidewalls
and
bottom
.
Beltstructural
damage,
glazed
or
shiny

sidewaljs
caused
by
a
loose
belt,
orseparation
are
al¡
reasons

to
replace
a
belt
.

Replacement
of
the
V-belts
every
four
years
is
recommend-

ed
.
Loosen
the
mounting
bolts
and
adjust
the
belt-driven
unit

until
the
belt
tension
is
as
loose
aspossible
.
Remove
the
belt
by

slipping
it
over
the
pulleys
.
In
some
cases
it
may
be
necessary

to
removeone
V-belt
to
get
to
another
.
Use
a
torque
wrench
and

a
crowfoot
wrench
to
turn
the
tensioning
gear
bolt
and
set
belt

tension
.
Hold
the
wrench
steady
and
tighten
the
locknut
on
the

rear
of
the
tensioning
gear
bolt
.
Tighten
al¡
other
mounting
nuts
.

MAINTENANCE
PROGRAM



020-
1
3

NOTE-

"
For
the
most
accurate
check,
V-belt
tension
should
be
checked
using
a
V-belt
tension
gauge
.

"
Belt
squealing
is
normally
caused
by
loose
beltten-sion
.
Belt
dressings
should
not
be
used
.

Tightening
Torques

"
Tensioning
gear
(alternator

belt
tensioning)
.
.
.
...............
7
Nm
(62
in-lb)

"
Tensioning
gear(power
steering

belt
tensioning)
...
..
...
8
to
8
.5
Nm
(71
to
75
in-lb)

"
Tensioning
gear
locking
nut
.......
24
Nm
(18
ft-Ib)

NOTE-

When
belts
are
replaced
with
new
ones,
store
the
old
set
in
the
luggage
compartment
for
emergency
use
.

When
installing
a
new
belt,
gently
pry
it
over
the
pulleys
.
Too

much
force
may
damage
the
belt
or
the
accessory
.
Tension
the

belt(s),
runthe
engine
for
a
few
minutes
(at
least
1500
rpm),

then
recheck
the
belt
tension
.

CAUTION-

Do
not
over
tighten
the
V-belts
.
Overtightening
will
cause
shaft
bearings
to
fail
prematurely
.

Poly-ribbed
belt,
replacing

(4-cylinder
engines
buiit
from
1194

and
all
6-cylinder
engines)

An
automatic
belt
tensioner
is
used
to
keep
the
belts
ten-

sioned
properly
.
Unless
the
tensioner
mechanism
malfunc-

tions,
the
poly-ribbed
belts
do
not
require
tension
adjustment
.

To
reduce
the
chance
ofbelt
failure
while
driving,
replace-

ment
of
the
belts
every
four
years
is
recommended
.
Mark
drive

belt
rotationdirectíon
if
removing
and
reusing
an
old
belt
.

To
remove
the
belt,
it
is
necessary
toretract
the
self-tension-

er
.
Using
a
breaker
bar
or
other
long
socket
assembly,
rotate

the
tensioner
to
loosenthe
belt
.
See
Fig
.
14
or
Fig
.
15
.
On
4-cyl-

inder
engines,
it
will
benecessary
to
remove
the
A/C
compres-

sor
belt
to
remove
the
main
drive
belt
.

WARNING
-

Observe
care
when
replacing
the
belt
.
Personal
in-
jury
could
result
if
the
tensioner
springs
back
into
position
uncontrollably
.

With
the
belt
removed
from
the
pulleys,
inspect
the
pulleys

for
wear
or
damage
that
may
cause
early
failureof
the
new
belt
.

This
is
also
a
good
opportunity
to
inspect
the
belt-driven
acces-

sories,
checking
for
bearing
wear
and
excess
play
.
Drive
belt

routing
is
shown
in
Fig
.
16
and
Fig
.
17
.

ENGINE
COMPARTMENT
MAINTENANCE

100-2
ENGINE-GENERAL

Cylinder
Head
and
Valvetrain

The
aluminum
cylinder
head
uses
chain-driven
double
overhead
camshafts
and
four
valves
per
cylinder
.
See
Fig
.
1
.

The
cylinder
head
employs
a
crossflow
design
for
greater

power
and
efficiency
.
Intake
air
enters
the
combustion
cham-

ber
from
one
side
while
exhaust
gasses
exit
from
the
other
.

Oílways
in
the
head
provide
lubrication
for
the
camshafts)
and
valvetrain
.

Fig
.
1
.



M52
twin-cam,
4-valve-per-cylinder
engine
with
hydraulíc
lift-
ers
.

On
all
engines
exceptthe
M44
engine,
valveclearance
is
by
seif-adjusting
hydraulic
lifters
.
On
M44
engines,
instead
of
hy-

draulic
lifters,
hydraulic
pedestaisare
used
in
combination
with
roller
rocker
arms
to
actuate
the
valves
.
Hydraulic
pedes-
tals
have
the
same
function
as
hydraulic
lifters,
which
ís
to
maintain
zero
valve
clearance,
reduce
valve
noise,
and
elimí-
nate
routíne
adjustment
.
See
Fig
.
2
.

VANOS
(Variable
Valve
Timing)

GENERAL

1
.
Camshafts
2
.
Rocker
arms
3
.
Hydraulic
valve
adjusters
(HVA)
4
.
Valve
and
conical
valve
spring

4

Fig
.
2
.



Cross
sectionof
M44
twin-cam,
4-valve-per-cylinder
head
.
Note
function
of
hydraulíc
pedestal
in
combination
with
rock-er
arm
(with
roller
bearing
for
reduced
friction)
.

The
main
components
of
the
VANOS
system
arethe
piston

housing
with
integral
spool
valve
and
solenoid,
and
the
modi-

fied
intake
camshaft
and
sprocket
assembly
.
See
Fig
.
3
.

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



B11001

able
intake
valve
timing
system,
known
as
VANOS
(from
the
German
words
Variable
Nockenwellen
Steuerung)
.
The



Fig
.
3
.
VANOS
(variable
intake
valve
timing)
systemusedon
M52
en-
VANOS
system
electro-hydraulically
adjusts
intake
valve
tim-



gine
.
When
solenoid
is
actuated,
oíl
pressure
is
directed
to
ingfor
enhanced
mid-range
performance
.
The
VANOS
sys-



front
side
of
gear
cup
piston
.
This
forces
gear
cup
finto
camtem
is
controlled
by
the
engine
control
module
(ECM),
using



shaft
to
advance
intake
valve
timing
.
enginespeed,engine
load
and
engine
temperature
asthe
pri-
mary
inputs
.



When
the
engine
is
running,
the
piston
housing
is
supplied
with
pressurized
engine
oil
víathe
solenoid-actuatedspool
At
low
speeds,
the
intake
valves
open
late
to
ensure
smooth



valve
.
Depending
on
the
position
of
the
spool
valve,
oil
isdi
engine
operation
.
At
mid-rangespeeds,
thevalves
open
early



rected
to
either
the
front
or
back
side
of
the
gear
cup
piston
.
(valvetiming
advanced,
VANOS
actuated)
for
increased
torque,
improved
driveability,
and
reduced
emissions
.
And
at



When
the
solenoid
isin
the
off
position,
engine
oíl
is
direct-
high
speeds,
the
valves
again
open
late
for
optimum
power



ed
to
the
back
side
of
the
piston
.
This
holds
the
gear
cup
for-
and
performance
.



ward
and
valve
timing
is
maintained
at
the
normal
"late"
position
.
When
the
solenoid
is
energized,
the
spoolvalve
is
moved
forward
and
oil
pressure
is
directed
to
the
front
side
of
the
piston
.
This
in
turn
moves
thegear
cup
further
into
the

camshaft
secondary
drive,
causing
thecamshaft
to
"advance"

12
.5°
.
The
helical
gears
are
cut
so
that
forward
motion
of
the

gear
cup
is
transiated
into
rotational
motion
of
the
camshaft
.

See
117
Camshaft
Timing
Chain
for
testing
and
repair
infor-
mation
on
the
VANOS
system
.

DISA
(Dual
Resonance
Intake
System)

DISA,usedon
4-cylinder
engines,
is
a
dual
intake
runner

system
that
effectively
provides
the
advantages
of
both
short

and
long
intake
runners
within
the
same
engine
.
For
best
per-

formance,
long
intake
runners
aremost
beneficial
atlow-
and
mid-engine
speeds
(below
4,200
rpm),
and
short
intake
run-
ners
enhance
torque
at
high
engine
speeds
(above4,200
rpm)
.

NOTE-

The
term
DISA
comes
from
the
German
words
Differ-
enzierte
Sauganlage,
and
can
roughty
be
transiated
as
a
differing
intake
manifold
configuration
.

The
DISA
solenoid
valve
is
controlled
by
the
DME
control

module,
using
engine
speed
as
the
primary
input
.
The
main

components
of
the
system
are
the
modified
twin-section
in-

takemanifoldwith
change-over
valve,
the
twin-barrel
throttle

body,
and
the
electrical/pneumatic
actuating
components
.

See
Fig
.
4
.

r

I

I

I

?
,
in
UpPer,
take
-1
manifold

1
-1
Throttle
housing
(Heated)

q
:lZU

Fig
.
4
.



DISA
system
components
.
DISA
changes
the
intake
runner

length
based
on
engine
speed
.

The
DISA
system
electro-pneumatically
changes
the
intake
runner
length
through
the
twin-section
intake
manifold
and
a
change-over
butterfly
valve
.
The
change-over
valve
is
located
at
a
point
in
the
intake
manifold
where
four
pipes
come
into
two
.
When
the
change-over
valve
is
closed,
the
4-way
primary
intake
manifold
and
the
2-way
ram
air
manifold
areconnected
to
make
the
"long"
configuration
.
When
the
change-overvalve
opens,
intake
air
flow
is
redirected
through
only
the
short
4-

way
primary
intake
manifold
.

The
change-over
valve
is
held
in
the
normally
open
position
bya
spring
.
Thisallows
for
an
open
valve
in
the
event
of
sys-
tem
failure
.
During
low
andmid
enginespeeds,
the
DME
con-

trol
module
supplies
power
to
the
solenoid
valve,
which
in
turn

allows
vacuum
to
be
applied
lo
the
vacuum
diaphragm
.
This

causes
the
valve
to
close
(long-pipe
configuration)
.
When
en-
gine
speed
reaches
approximately
4,800
rpm,
the
DME
con-
trol
module
electrically
signals
the
solenoid
valve
and
the
valve
opens,
creating
the
short
pipe
configuration
:

Further
detafs
on
DISA
canbefound
in
130
Fuel
Injection
.

Engine
Management
System

Al¡
enginescoveredby
this
manual
usean
advanced
engine

management
system
called
Digital
Motor
Electronics
(DME)
.

In
the
DME
system,
advancedOn-Board
Diagnostics
(OBD),

fuel
injection,
ignition,
and
otherfunctions,
are
combined
under

the
control
of
theEngine
Control
Module
(ECM)
.
See
Fig
.
5
.

-



Lower
intake
manifold

DISAvacuum
'
~servo

EíY1z

ENGINE-GENERAL
100-
3

le

-
DISA
solenoid
valve

0012591

/
with
butterfly
va¡

GENERAL