1992 BMW 318i 001

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

020-
1
4



MAINTENANCE
PROGRAM

uu11989

Fig
.
14
.
Engine
drive
belt
tensíoner
being
released
on
late
4-cylinder
engine
.
Pry
off
tensioner
cover
and
then
lever
tensioner
in
clockwise
direction
(as
facing
engine)
and
slip
beltoff
pulleys
.



Fig
.
17
.
Engine
drive
belt
routing
for
late
4-cylinder
engine
with
poly-
ribbed
drivebelts
.

CA
UTION-

Use
only
BMW
approved
phosphate-free
anti-
freeze
when
filling
the
cooling
system
.
Use
of
anti-

B11177



freeze
containing
phosphates
!s
considerad
to
be

Fig
.
15
.
Engine
drive
belt
tensioner
being
released
on
6-cylinder
en-



harmful
to
the
cooling
system
.

gine
.
Pry
off
tensioner
cover
and
then
lever
tensioner
in
clock-
wise
direction
(as
facing
engine)
and
slipbelt
off
pulleys
.



A
translucent
expansion
tank,
or
overflow
resenroir,
providesmonitóring
of
coolant
leve¡
.
Because
the
expansion
tank
is
translucent,
thecoolant
level
can
be
checked
visually
without
opening
the
system
.
Always
check
thecoolant
leve¡
with
theen-gine
cold
.
The
coolant
leve¡
should
be
at
the
maximum
mark
on
O



o
'~
I



the
expansion
tank,
as
shown
in
Fig
.
18
.

OO



Hose
connectionhld
b
tiht
s
soueg



an
ddry
.
Coolánt
seepage
indicates
either
that
the
hose
clamp
is
loose,
that
the
pose
is

ENGINE
COMPARTMENT
MAINTENANCE

0012470

Fig
.
16
.
Engine
drive
belt
routing
for
6-cylinder
engine
.
A/C
compres-
sor
drive
belt
not
shown
.

'92

irá
Alternator
belt

Coolant~
0
pp



o0o



Belt
tensioner

Cooling
System
Service

0013000

Cooling
system
maintenance
consists
of
maíntaining
thecoolant
leve¡,
inspecting
hoses
.
Because
the
coolant's
anti-cor-

rosion
and
anti-freeze
additives
gradually
lose
their
effective-
ness,
replacement
of
thecoolant
every
two
years
up
to
1996
models,
and
every
three
years
from
1996
is
recommended
.
Asa
preventive
measure,
replacement
of
the
cooling
system
hos-
es
every
four
years
is
also
recommended
.

damaged,
or
that
the
connection
is
dirty
or
corroded
.
Dried
cool-
ant
has
a
chalky
appearance
.
Hoses
should
be
firm
and
springy
.
Replace
any
hose
that
is
cracked,
that
has
become
soft
and
limp,
or
has
been
contaminated
by
oil
.
See
Fig
.
19
.

Power
steering
fluid,
checking
leve¡

Check
the
power
steering
fluid
level
in
the
fluid
reservoir
.
Park
thecar
on
leve¡
ground
with
the
engine
off
.
The
level
is
cor-
rect
if
it
is
between
the
MIN
and
MAX
marks
on
the
dipstick
.
See
Fig
.
20
.
If
the
leve¡
is
below
the
MIN
mark,
start
the
engine
andadd
fluid
to
the
reservoir
to
bríng
the
leve¡
up
.
Stop
the
engine
and
recheck
the
leve¡
.
Hand-tighten
the
reservoir
cap
.

Fig
.
18
.
Fill
mark
on
coolant
expansion
tank
.
Coolant
level
should
be

at
mark
when
engine
ís
cold
.

.
..
e
..
.-
..



~
..
.-
.

Ozone
Damaged
Hose

0012476

Fig
.
19
.
Examples
of
damage
to
coolant
hoses
.
Any
of
conditions

shown
is
cause
for
replacement
.
Courtesy
of
Gates
Rubber
Company,
Inc
.

Specification

"
Power
steering
fluid
..........
.
...
Dexron
III®ATF

Oxygen
Sensors

1996
and
later
engines
are
equipped
withmultiple
oxygen

sensors
.
See
Fig
.
21
.
A
regulating
sensor
is
mounted
before

each
catalytic
converter
and
amonitoring
sensor
downstream

of
each
converter
.
The
regulating
sensor
monitors
engine
com-

bustion
efficiency
and
helps
to
control
the
fuel
injection
system

and
exhaust
emissions
.
The
monitoring
sensor
is
usedby
the

On-board
diagnostic
system
to
monitor
the
function
of
the
cata-

lytic
converter
.

MAINTENANCE
PROGRAM



020-
1
5

NOTE-

5pecialsockets
for
replacingthe
oxygen
sensor
are

available
from
most
automotive
parts
stores
.
The
sock-

et
has
agroove
cut
down
one
side
to
allow
the
sensor

to
be
installed
without
damaging
the
wire
hamess
.

Fig
.
20
.
Power
steering
fluid
dipstick
showing
MIN
and
MAX
marks
.

OBD
II
enhanced
emission
standards
require
the
engine

control
module
(ECM)
to
monitor
the
oxygen
content
in
theex-

haust
bothbefore
and
after
the
catalytic
converter
.
This
allows

for
tightercontrol
of
the
tail
pipe
emissions
and
also
allowsthe

ECM
to
diagnose
converter
problems
.
lf
the
DME
detects
that

catalytic
converter
or
oxygen
sensor
efficiency
has
degraded

past
a
certain
pre-programmed
limit,
it
will
turn
on
the
Check

Engine
light,
and
store
a
diagnostic
trouble
code
(DTC)
in
the

ECM
.

Replacement
of
oxygen
sensors
at
the
specified
intervals
en-

sures
that
the
engine
and
emission
control
system
wíll
continue

to
operate
as
designed
.
Extending
the
replacement
interval

may
void
the
emission
control
warranty
coverage
.
See
180
Ex-

haust
System
for
information
on
replacing
the
oxygen
sen-

sors
.

Tightening
Torque

"
Oxygen
sensor
to

exhaust
system
........
.
.
.
..
55±5
Nm
(40±4
ft-Ib)

ENGINE
COMPARTMENT
MAINTENANCE

020-
1
6



MAINTENANCE
PROGRAM

Fuel
filter,
replacing

Oxygen
sensor

(regulating)
\
Catalytic



Oxygen
sensor
convertor
(monitoring)

Fig
.
21
.
Typical
1996
and
later
exhaust
system
showing
oxygen
sensor
locations
.

UNDER-CAR
MAINTENANCE

convertor

On
early
4-cylínder
cars,
the
fuel
filter
is
mounted
under
the
caron
the
left
front
bulkhead
.
On
early
6-cylínder
cars,
the
fuel
filter
is
mounted
to
the
front
left
motor
mount
in
theengine
com-
partment
.
See
Fig
.
22
.

0013139
Fig
.
22
.
Fuel
filter
location
(arrow)
on
bulkheadunder
left
side
of
vehi-
cle
.
Filter
for
M42
engine
shown
.

On
later
cars,
the
fuel
filter
is
located
beneath
the
centerof
the
car,
approximately
under
the
driver's
seat
.
See
Fig
.
23
.
A
protective
cover
is
installed
overthe
fuel
filter,
which
must
be
re-
moved
to
access
the
filter
.

UNDER-CAR
MAINTENANCE

Exhaust
flap

actuator

(monitoring)

NOTE-

Drain
the
fuel
filter
trom
the
inlet
side
into
a
container
and
inspect
the
drained
fuel
.
Check
for
rust,
moisture
and
contamination
.

WARNING
-
Fuel
will
be
expelled
when
the
filter
is
removed
.
Do
not
smoke
or
worknear
heaters
or'other
fire
haz-ards
.
Keep
a
tire
extinguisher
handy
.

CAUTION-

Clean
thoroughly
around
the
filter
connections
be-
fore
removing
them
.

0012726
Fig
.
23
.
Fuel
filter
location
under
center
of
car
(arrow)
.
Filter
for
M52
engine
shown
.

Catálytic
\
Oxygen
sensor

When
replacing
the
fuel
filter,
disconnect
the
battery
negative
(-)
cable
and
clamp
the
filter
inlet
and
outlet
hoses
to
lessen
fuel
spillage
.
Loosen
thecenter
clamping
bracket
and
the
two
hoseclampson
either
end
of
the
filter
.
Note
the
arrow
or
mark-
ings
indicating
direction
of
flow
on
the
new
filter
.
Install
the
filter
anduse
new
hose
clamps
.

020-
1
8



MAINTENANCE
PROGRAM

Fig
.
25
.
Inspect
brake
pads
with
the
caliper
removed
.
Minimum
brake
pad
thickness
shown
by
dimension
(A)
.

NOTE-

The
parking
brake
may
lose
some
of
its
effectiveness
if
it
is
not
used
frequently
.
This
is
due
to
corrosion
build-
up
on
the
parking
brake
drum
.
To
remove
corrosion,
ap-
plythe
parking
brake
just
until
it
begins
togrip,
then
pulí
the
lever
up
one
more
stop
(click)
.
Drive
thecar
approx-
imately
400
meters
(1,300
ft
.)
and
release
the
brake
.
To
recheck
the
adjustment
of
the
parking
brake
see340
Brakes
.

UNDER-CAR
MAINTENANCE

0011920

Manual
transmission
fluid,

checking
and
filling

The
manual
transmission
fluid
leve¡
should
be
checked
at

specified
intervals
.
Check
and
fill
the
transmission
with
the
car

ona
leve¡
surface
.
Transmission
(luid
leve¡
checking
and
re-

placement
procedures
are
covered
in
230
Manual
Transmis-

sion
.

Automatic
Transmission
Service

The
automatic
transmission
is
not
equipped
with
a
dipstíck
.

Therefore,
checking
the
ATF
level
is
an
ínvolved
procedure,

which
includes
measuring
and
maintaining
a
specified
ATF

temperature
during
the
checking
procedure
.

For
more
complete
ATF
service,
including
checking
ATF
lev-

e¡
and
ATF
filter
replacement
procedures,
see
240
Automatic
Transmission
.

Front
suspension
and
steering
linkages,

inspecting

Inspection
of
the
front
suspension'and
steering
includes
a
check
of
all
moving
parts
for
wear
and
excessive
play
.
Also
in-

spect
the
rubber
seals
and
boots
for
cracks
or
tears
that
could

allow
the
entry
of
dirt,
water,
and
other
contaminants
.
See
310

Front
Suspension
.

Exhaust
system,
inspecting



Rear
suspension,
inspecting
Exhaust
system
life
varies
widely
according
to
driving
habits



Final
drive
and
rear
drive
axle
service
consists
of
checking

and
environmental
conditions
.
If
short-distance
driving
pre-



and
changing
the
gear
oil,
inspecting
for
leaks,
and
checking
dominates,
the
moisture
and
condensation
in
the
system
will



the
rear
drive
axle
rubber
boots
for
damage
.
not
fully
dryout
.
This
will
lead
to
early
corrosion
damage
and
more
frequent
replacement
.
The
areas
where
leaks
are
most
likely
to
occur
are
around
the
driveshaft
and
drive
axle
mounting
flanges
.
For
more
infor

Scheduled
maintenance
of
the
exhaust
system
is
limitedlo



mation
on
ídentifying
oil
leaks
and
their
causes,
see330
Rear
inspection
.
Check
for
restrictions
due
to
dents
or
kinks
.
Check



Suspension
.
for
weakness
or
perforation
due
to
rust
.
Check
lo
see
that
all
the
hangers
are
in
place
and
properly
supporting
the
system
and
that
the
system
does
not
strike
the
body
.
Alignment
of
the
sys-



Final
drive
oil
leve¡,
checking

temand
the
location
of
the
hangers
aredescribed
in
180
Ex-
haust
System
.



Check
the
lubricant
leve¡
with
thecar
level
.
Remove
the
oil
filler
plug
.
The
leve¡
is
correct
when
the
fluidjust
reaches
the

edge
of
the
filler
hole
.
Install
and
tighten
the
oil
filler
plug
when
Manual
Transmission
Service



the
oil
level
is
correct
.
See
Fig
.
26
.

Manual
transmissionservice
consists
of
inspectingfor
leaks



The
final
drive
should
be
filled
with
a
special
BMW
lubricant
and
checking
and
changing
the
fluid
.



available
through
an
authorized
BMW
dealer
.
In
addition,
the
lubricant
type
varies
depending
onwhether
or
nota
limited-slip
Evidence
of
transmissionleaks
is
fkely
to
beseenaround
the



differential
is
fitted
.
driveshaft
mounting
flange
and
at
the
bottom
of
the
bellhousing
.
For
more
information
on
identifying
oil
leaks
and
their
causes,
see230ManualTransmissionand210
Clutch
.



Tightening
Torque

"
Finaldrive
filler
plug
to
final
drive
housing
..................
70
Nm
(52
ft-Ib)

NOTE-

Use
a14
mm
or17
mm
alíen
bit
socket
to
remove
the
drain
plug
.

"
If
thecar
is
raised
in
the
air,
it
shouldbe
leve¡
.

Fuel
tank
and
fuel
fines,
inspecting

0012474

Inspect
the
fuel
tank,
fuel
lines,
and
fuel
system
for
damage

or
leaks
.
Check
for
fuel
leaks
in
the
engine
compartment
or

fuel
odors
in
the
passenger
compartment
.
Check
for
faultyfuel

lines
bybending
them
.
If
any
leaks
are
present,
fuel
should
be

expelled
.
Check
for
any
evaporative
emissions
hoses
that

may
have
become
disconnected,
checking
carefully
at
the

charcoal
canister
and
evaporative
emissionspurge
system
.

See130
Fuel
Injection
and
160
Fuel
Tank
and
Fuel
Pump

for
component
locations
and
additional
information
.

WARNING
-

When
checking
for
fuel
leaks,
the
engine
must
be
cold
.
A
hot
exhaust
manifold
or
exhaust
system
could
cause
the
fuel
to
ignite
or
explode
causing
se-
rious
personal
injury
.
Uentilate
the
workarea
and
clean
up
spilled
fuel
immediately
.

Clutch
fluid,
checking

The
hydraulic
clutch
and
the
brake
system
share
the
same

reservoir
and
the
same
brake
fluid
.
Clutch
fluid
leve¡
and
brake

fluid
level
are
checked
at
the
same
time
.
See340
Brakes
for

more
information
.
See210
Clutch
for
information
on
the
clutch

and
the
hydraulic
clutch
operating
system
.

MAINTENANCE
PROGRAM



020-19

Drive
axie
joint
boots,
inspecting

100
Engine-General

The
protective
boots
must
be
closely
inspected
for
cracks
andany
other
damage
that
will
allow
contaminants
to
get
ínto
the
joint
.
If
the
rubber
boots
faf
,
the
water
and
dirt
that
enter
the
joint
will
quickly
damage
¡t
.
Replacement
of
the
drive
axle
joint
boots
and
inspection
of
the
joints
are
described
in
330
Rear
Suspension
.

BODY
AND
INTERIOR
MAINTENANCE

Windshield
Wiper
Biade
Maintenance

Common
problems
with
the
windshield
wipers
include

streaking
or
sheeting,
water
drops
after
wiping,
and
blade
chat-

ter
.
Streaking
is
usually
caused
when
wiper
blades
are
coated

with
road
film
or
car
wash
wax
.
Clean
the
blades
using
soapy
water
.
If
cleaning
theblades
does
not
cure
the
problem
then

they
should
be
replaced
.
BMW
recommends
replacing
the
wip-
er
blades
twice
a
year,
before
and
after
the
cold
season
.
Onold-

er
cars,
check
the
tension
spring
that
holds
the
wiper
to
the

glass
.
Replace
the
wiper
arm
if
the
springs
are
weak
.

Drops
that
remainbehind
after
wipingare
caused
by
oil,
road

film,
or
diesel
exhaust
coating
the
windshield
.
Use
an
alcohol
or

ammonia
solution,
or
a
non-abrasive
cleanser
to
clean
the

windshield
.

Wiper
blade
chatter
may
be
caused
by
dirty
or
worn
blades,

bya
dirty
windshield,
or
by
bentor
twisted
wiper
arms
.
Clean

the
blades
and
windshield
as
described
above
.
Adjust
the
wiper

arm
so
that
there
is
even
pressure
along
the
blade,
and
so
that

the
blade
is
perpendicular
to
the
windshield
atrest
.
Lubricate

the
wiper
linkage
with
a
light
oil
.
The
linkage
is
located
under

the
hood
on
the
drivers
side
.
If
the
problem
persists,
theblades
are
excessively
aged
or
worn
and
should
be
replaced
.
See
611
Wipers
and
Washers
.

Body
and
hinges,
lubricating

The
door
locks
and
lock
cylinders
canbe
lubricated
with
an

oil
that
contains
graphite
.

The
body
and
door
hinges,
the
hood
latch,
and
the
door

check
rods
should
be
lubricated
with
SAE
30
or
SAE
40
engine

oil
.
Lubricate
the
seat
runners
with
multipurpose
grease
.
Do
not

apply
any
oil
to
rubber
parts
.
If
door
weatherstrips
are
sticking,

lubricate
them
with
silicone
spray
or
talcum
powder
.
The
hood

release
cable
should
be
lubricated
as
well
.

The
use
of
winter
lock
de-icer
spraysshould
be
kept
to
an
ab-

solute
minimum,
as
the
alcohol
in
the
de-icer
will
wash
the

grease
out
of
the
lock
assemblies,
and
may
cause
the
locks
to

corrode
internally,
or
become
difficult
to
operate
.

ENGINE-GENERAL
100-1

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