wire BMW 318i 1997 E36 Repair Manual
[x] Cancel search | Manufacturer: BMW, Model Year: 1997, Model line: 318i, Model: BMW 318i 1997 E36Pages: 759
Page 185 of 759
160
Fuel
Tank
and
Fuel
Pump
GENERAL
.
.
.
.
.
.
...........
.
....
.
.
.
.
.
.
160-1
Operating
fuel
pump
for
tests
.
.
.
.
.
.
.......
.160-6
Fuel
Pump
Electrical
Tests
.
.
.
.
.
.
.
...
.
.
.
.
.
160-7
FUEL
TANK
AND
LINES
..
.
.
.
..........
160-2
Fuel
pump
electrical
circuit,
testing.
...
.
.
.
.
.
160-7
Fuel
tank,
draining
..
.
.
.
.
.
.
.
.
.
..........
160-2
Fuel
pump
power
consumption,
testing
.
.
.
.
.
.
160-7
Fuel
tank,
removing
and
installing
.........
160-3
Fuel
Delivery
Tests
....
.
.
.
...
.
.....
.
.
.
..
160-8
Fuel
Tank
Evaporative
Control
System
.....
160-4
Relieving
fuel
pressure
and
connecting
fuel
pressure
gauge
..
.
...........
.
.
.
..
160-8
FUEL
LEVEL
SENDERS
.
.
.
.
.
.......
.
.
.
160-4
System
pressure,
testing
.................
160-9
Fuel
level
senders,
testing
.
.
.
.
.
.......
.
.
.
160-5
Fuel
delivery
volume,
testing
.............
160-10
Fuel
leve¡
sender
and
fuel
pump
(right
side),
emoving
and
installing
.
.
.
.
.
.
160-5
TABLES
Fuel
leve¡
sender
(left
side),
a
.
FuelLeve¡
Sender
Resistances
...........
.
.
..
.160-5
removing
and
installing
.........
.
.
.
.
.
.
.
160-6
b
.
Fuel
Pump
Current
...
.................
..
...
160-8
c
.
Fuel
Pressure
Specifications
..............
.
..
160-10
FUEL
PUMP
.
.
.
................
.
.
.
.
.
.
.
160-6
d
.
Fuel
Pump
Delivery
Specifications
.........
.
..
160-10
Fuel
Pump
Fuse
and
Relay
.
.
.
....
.
.
.
.
.
.
.
160-6
GENERAL
This
repair
group
covers
service
information
specifically
for
The
cautions
and
warnings
on
this
page
should
beob
the
fuel
supply
system
.
Information
on
the
fue¡
injection
sys-
served
when
servicing
the
fuel
system
.
tem
is
covered
in
130
Fuel
Injection
.
NOTE-
Fue¡
filter
replacement
is
covered
in
020
Maintenance
Program
.
WARNING
-
"
The
fuel
system
is
designed
to
retain
pressure
even
when
the
ignition
isoff
.
When
working
with
the
fuel
system,
loosen
the
fuel
lines
slowly
toal-
low
residual
fuel
pressure
to
dissipate
gradually
.
Avoid
spraying
fuel
.
"
Before
beginning
any
work
on
the
fuel
system,
place
a
tire
extinguisher
in
the
vicinity
of
the
work
area
.
"
Fuel
is
highly
flammable
.
When
working
around
fuel,
do
not
disconnect
any
wires
that
could
cause
electrical
sparks
.
Do
not
smoke
or
work
near
heaters
or
other
tire
hazards
.
"
Always
unscrew
the
fuel
tank
cap
to
release
pres-
sure
in
the
tank
before
working
on
the
tank
or
fines
.
"
Do
not
use
a
work
light
near
any
fuel
.
Fuel
may
spray
onto
the
hot
bulb
causing
a
tire
.
"
Make
sure
the
work
area
is
properly
ventifated
.
FUEL
TANK
AND
FUEL
PUMP
160-1
CAUTION-
"
Prior
to
disconnecting
the
battery,
read
the
bat-tery
disconnection
cautions
given
at
the
front
of
this
manual
onpage
viü
.
"
Before
making
any
electrical
tests
with
the
ignition
tumed
on,
disable
the
ignition
system
as
de-
scribed
in
120
Ignition
System
.
Be
sure
the
bat-tery
is
disconnected
when
replacing
components
.
"
To
prevent
damage
to
the
ignition
system
or
the
electronic
fuel
system
components,
including
the
control
unit,
aiways
connect
and
disconnect
wires
and
test
equipment
with
the
ignition
off
.
"
Cleanliness
is
essential
when
working
with
the
fuel
system
.
Thoroughly
clean
the
fuel
fine
unionsbefore
disconnecting
any
of
the
fines
.
"
Use
only
clean
tools
.
Keep
removed
parts
clean
and
sealed
or
covered
with
a
clean,
lint-free
cloth,
especially
if
completion
of
the
repair
is
delayed
.
"
Do
not
move
the
car
while
the
fuel
system
is
open
.
"
Avoid
using
high
pressure
compressed
air
to
blow
out
fines
and
componente
.
High
pressure
can
rupture
infernal
seals
and
gaskets
.
"
Always
replace
seals
and
O-rings
.
GENERAL
Page 189 of 759
Fuel
leve¡
senders,
testing
Fuel
leve¡
sender
(right
side)
The
left
and
right
fuelleve¡
sending
units
are
wired
in
series
.
and
fuel
pump,
removing
and
installing
The
fuel
gauge
receives
a
signal
that
is
the
average
of
the
two
1
.
Disconnect
negative
(-)
cable
from
battery
.
input
values
.
1
.
Remove
rear
seat
cushion,
lift
up
insulation
mats,
andremove
both
fuel
tank
access
covers
.
2
.
Disconnect
white
plug
on
each
sending
unit
.
See
Fig
.
6
.
3
.
Check
resistance
value
of
eachsending
unit
.
Values
should
be
the
same
.
5
.
If
valuesare
different,
remove
sending
units
as
described
below,
and
check
resistance
valuésacross
terminals
.
Table
a
lists
resistance
values
for
senders
at
various
float
positions
.
Table
a
.
Fuel
Leve¡
Sender
Resistances
Float
position
Test
result
(ohms)
Right
side
empty
10
ohm
t2
Right
side
full
250
ohm
±
5
Left
side
empty
10
ohm
t
2
Left
side
fui¡
250
ohm
±
5
FUEL
TANK
AND
FUEL
PUMP
160-
5
CAUTION
-
Prior
to
disconnecting
the
battery,
read
the
battery
disconnection
cautionsglven
at
the
front
of
this
manual
onpage
viii
.
2
.
Drain
fuel
from
tank
as
described
earlier
.
WARNING
-
Always
unscrew
the
fuel
tank
cap
to
release
pres-
sure
in
the
tank
before
working
on
the
tank
or
fines
.
3
.
Remove
rear
seat
cushion
and
pull
back
insulation
pad
under
right
side
.
4
.
Remove
screws
holding
rightfuel
tank
accesscover
.
Remove
cover
.
5
.
Label
fuel
hoses
.
Disconnect
hoses
and
harness
con-
nectors
from
fuel
sending
unit
and
fuel
pump
.
6
.
Unscrew
threaded
collar
from
fuel
pumplfuel
leve¡
sender
.
Slowly
withdraw
assembly
from
tank,allowing
fuelto
drain
off
.
See
Fig
.
7
.
0013187
&
0013194
Fig
.
6
.
Fuel
pump/leve¡
sender
terminal
identification
.
Check
resis-
tance
at
terminals
of
white
connectors
(arrows)
.
"
If
necessary,
push
leve¡
sender
arm
toward
fuel
pump
assembly
to
facilitate
removal
.
NOTE
-
BMW
special
tool
no
.
16
1
020
should
beused
to
re-
move
and
install
the
threaded
collar
.
Damage
to
the
collar
may
result
if
the
special
tool
is
not
used
WARNING
-
NOTE-
Fuel
may
be
spilled
.
Do
not
smoke
or
work
near
The
compensating
siphon
pump
(Fig
.
1)
maintains
the
heaters
or
other
fire
hazards
.
fuel
leve¡
between
the
right
and
left
tank
lobes
.
If
the
re-
sistances
are
different
between
the
left
and
right
send-
ers,
remove
the
senders
and
visually
inspect
the
leve)
in
7
.
Using
a
new
sealing
ring,
install
pump
and
sending
each
lobe
.
If
the
leve¡
is
different,
check
the
siphon
com-
unit,
being
sure
that
fuel
line
connections
point
in
same
pensating
pump
.
direction
as
they
carne
out
.
8
.
Reconnect
harnessconnector
and
hoses
.
Fill
tank
and
check
for
leaks
by
running
engine
.
Insta¡¡
access
cover
and
its
mountingscrews
.
Reconnect
negative
(-)
cable
to
battery
.
CAUTION
-
Before
starting
the
engine,
fill
the
fuel
tank
with
at
least
1
.5
gallons
(5liters)
of
fuel
.
The
pump
will
be
damaged
if
you
run
it
without
fuel
.
FUEL
LEVEL
SENDERS
Page 190 of 759
160-
6
FUEL
TANK
AND
FUEL
PUMP
Fig
.
7
.
Fuel
sender
and
pump
assembly
.
To
operate
the
fuel
pump
for
testing
purposes
without
hav-
Fuel
leve¡
sender
(left
side),
ing
to
runthe
engine,
the
fuel
pump
relay
can
be
bypassed
to
removing
and
installing
powerthe
pump
directly
.
The
procedure
for
removing
and
replacing
the
left
side
fuel
To
runthe
fuel
pump,
remove
the
relay
and
connect
the
leve¡
sender
is
similar
tothat
used
for
the
right
side
.
There
is
socket
for
relayterminal
30
to
the
socket
for
relay
terminal
no
.
no
fuel
pump
on
the
left
side
.
87
with
afused
jumper
wire
.
Relay
terminal
identification
is
shown
in
Fig
.
9
.
After
completing
the
tests,
remove
the
jumper
wire
.
FUEL
PUMP
The
electric
fuel
pump
ís
mounted
in
the
fuel
tank
in
tandem
with
the
right
side
fuelleve¡
sender
.
The
fuel
pump
delivers
fuel
at
high
pressure
to
the
fuel
injection
system
.
A
pressure
regulator
maintains
system
pressure
.
The
quantity
of
fuel
sup-
plied
exceeds
demand,
so
excess
fuel
retums
to
the
fuel
tank
via
a
retum
líne
.
See
130
Fuel
Injection
for
more
information
on
system
pressure
and
the
fuel
pressure
regulator
.
NOTE
-
Fuel
pump
removalprocedures
are
given
earlier
under
Fuel
leve¡
sender
(right
side)
and
fuel
pump,
remov-
íng
and
installing
.
Fuel
Pump
Fuse
and
Relay
The
fuel
pump
is
operated
by
a
fuel
pump
relay
located
ín
the
power
distribution
box
.
The
fuel
pump
circuit
is
protected
by
fuse
no
.
18
located
in
the
power
distribution
box
.
See
Fig
8
.
FUEL
PUMP
0013142
Fuel
DM
E
PUMP
main
re
ay
rel
ay
0
aoo
o
~a
aao
ó
Fig
.
8
.
Fuel
pump
relay
location
in
power
distribution
box
.
The
DME
engine
control
module
(ECM)
and
the
DME
main
relay
supply
power
to
the
coi¡
sideof
the
fuel
pump
relay
.
Dur-
ing
starting,
the
fuel
pump
runs
as
long
as
the
ignition
switch
is
in
the
start
position
and
continues
to
run
oncethe
engine
starts
.
If
an
electrical
system
fault
interrupts
power
to
the
fuel
pump,
the
engine
will
notrun
.
Operating
fuel
pump
for
tests
CA
UTION-
Relay
locations
may
vary
.
Use
care
when
identify-
ing
relays
and
when
troubleshooting
the
electrical
system
at
the
fuselrelay
panel
.
The
fuel
pump
re-
¡ay
is
a
four
pin
relay
and
has
a
1.5
mm
2
red
wireat
terminal
30
in
the
relay
socket,
lf
in
doubt,
con-
sult
an
authorized
BMW
dealer
.
NOTE-
Thejumper
wire
shouldbe
1.5
mm2
(14
ga
.)
and
in-
clude
en
in-fine
fuse
holder
with
a16
amp
fuse
.
To
avoid
fuselrelay
panel
damage
fromrepeated
connect-
íng
and
disconnecting,
also
include
a
toggleswitch
.
A
heavy-duty
jumper,
BMW
tool
no
.
613
050,
fs
also
available
from
en
authorized
BMW
dealer
.
0013034,
If
the
pump
does
notrun
with
the
jumper
installed,
the
fault
could
be
in
the
fuel
pump
or
the
wiring
to
the
pump
.
Check
the
pump
and
its
wiring
as
described
below
.
Page 191 of 759
Fig
.
9
.
Fuel
pump
relay
terminal
identification
.
Fuel
Pump
Electrical
Tests
Troubleshooting
of
any
fuel
pump
fault
should
begin
with
checking
the
fuel
pump
fuse
and
the
fuel
pump
relay
.
The
DME
main
relay
should
also
be
checked
.
NOTE-
Special
tools
are
requíred
for
some
of
the
tests
de-
scribed
here
.
Fuel
pump
electrical
circuit,
testing
The
fuel
pump
electrical
circuit
diagram
is
shown
in
Fig
.
10
.
3
.
If
fuel
pump
does
not
run,
disconnect
black
harness
connector
from
tank
sender
unit
.
With
jumper
wire
con-
nectedas
described
in
step
2
above,
check
for
positive
(+)
batteryvoltage
at
harness
connector
terminals
.
See
Fig
.
11
.
FUEL
TANK
AND
FUEL
PUMP
160-
7
From
Main
Relay
(+15
power
with
key
in
run
From
B+juretion
point
orstartposition)
(batteryvoRageatalltirnes)
'
.5
RD/Nrr
1
.5
RD
1
.5
GNNI
From
Engine
2
.5
GNNI
Control
Module
15
2
.5
GNNI
Ground
(below
center
console)
Fig
.
10
.
Fuel
pump
electrical
circuit
.
30
-~
Relay
Fuel
Pump
8~T
I
1
s
ám
61
Front
Power
I
a
1
Distribution
Box
I_
16
WIRING
COLOR
CODE
BK
-
BLACK
BR
-
BROWN
Fuel
Pump
RD
-
RED
(in-tank)
M
YL
YELLOWGN
-
GREENBU
-
BLUE
1
VI
-
VIOLET
GY
-
GREY
WT
-
WHITE
PK
-
PINK
0011946
4
.
If
voltage
and
groundare
present,
fuel
pump
is
proba-
bly
faulty
.
If
there
is
no
voltage,
check
wiring
From
fuel
pump
Reay
and
make
sure
Reay
is
functioning
correctly
.
CAUTION-
Fuseandrelaylocationsmayvary
.
Usecara
when
Fuel
pump
power
consumption,
testing
troubleshooting
the
electrical
system
at
the
fuselrelay
panel
.
To
resolve
problems
in
identify-
NOTE-
ing
a
relay,
see
en
authorízed
BMW
dealer
.
"
To
achieveaccurate
testresults,
fhe
battery
voltage
at
the
connector
should
be
approximately
13
volts
.
1.
Remove
rearseat
cushion,
pull
right
side
insulation
mat
Charge
the
battery
asnecessary
.
back
to
expose
fuel
tank
accesscover
.
Remove
cover
.
q
higher
than
normal
power
consumption
usually
fin-
to
expose
wiring
connections
.
dicates
a
worn
fuel
pump,
which
may
cause
intermit-
tentfuel
starvation
due
lo
pump
overheating
and
2
.
Remove
fuel
pump
relay
and
opérate
fuel
pump
as
de-
seizure
.
The
only
remedy
is
pump
replacement
.
Be
scribed
under
Operating
fuel
pump
for
tests
earlier
.
sure
to
check
that
thereturn
fine
and
the
pump
pickup
Pump
should
run
.
Disconnect
jumper
wire
when
fin-
are
not
obstructed
before
replacing
the
pump
.
ished
.
1
.
Remove
rear
seat
cushion,
pull
right
side
insulation
mal
back
to
expose
fuel
tank
accesscover
.
Remove
cover
to
expose
wiring
connections
.
2
.
Disconnect
(black)
harness
connector
from
fuel
pump
.
3
.
Connect
an
ammeter
and
an
insulated
jumper
wire
be-
tween
terminals
in
connector
and
corresponding
pump
terminals
.
See
Fig
.
12
.
FUEL
PUMP
Page 192 of 759
160-
8
FUEL
TANK
AND
FUEL
PUMP
UU131
tst5
Fig
.
11
.
Voltage
supply
to
fuel
pump
harness
(black)
connector
being
checked
(arrow)
.
00131ts7
Fig
.
12
.
Test
fuel
pump
for
current
draw
by
attadhing
ammeter
andjumper
wire
as
shown
.
CAUTION-
Do
not
allow
the
test
leads
to
short
to
ground
.
NOTE-
See
600
Electrical
System-General
for
information
on
electricaltests
using
a
digital
multimeter
(DMM)
.
4
.
Run
pump
as
described
in
Operating
fuel
pump
for
tests
.
FUEL
PUMP
5
.
Compare
ammeter
reading
with
specification
listed
in
Table
b
.
Maximum
current
5
.0
amps
consumption
FuelDelivery
Tests
Table
b
.
Fuel
Pump
Current
Checking
fuel
delivery
is
a
fundamental
part
of
trouble-
shooting
and
diagnosing
the
DME
system
.
Fuelpressure
di-
rectly
influences
fuel
delivery
.
An
accurate
fuel
pressure
gauge
will
be
needed
to
make
the
tests
.
There
arethree
significant
fuel
delivery
values
to
bemea-
sured
:
"
System
pressure-created
by
the
fuel
pump
and
main-
tained
by
the
pressure
regulator
.
"
Fuel
delivery
volume-created
by
the
fuel
pump
and
af-
fected
by
restrictions,
suchas
clogged
fuel
filter
.
"
Residual
pressure-the
pressure
maintained
in
the
closed
system
after
the
engine
and
fuel
pump
areshut
off
.
Procedures
for
measuring
the
first
two
quantities
arede-
scribed
here
.
Residual
fuel
pressure
is
checked
using
the
procedurede-
tailed
in
130
Fuel
Injection
.
Relieving
fuel
pressure
and
connecting
fuel
pressure
gauge
WARNING
-
"
Gasoline
is
highly
flammable
and
its
vaporsare
explosive
.
Do
not
smoke
or
work
ona
car
near
heaters
or
other
fire
hazards
when
diagnosing
and
repairing
fuel
system
problems
.
Have
a
fire
extinguisher
available
in
case
of
an
emergency
.
"
When
working
onan
open
fuel
system,
wear
suit-
able
hand
protection
.
Prolonged
contact
with
fuel
can
cause
iflnesses
and
skin
disorders
.
CA
UTION-
Cleanliness
is
essential
when
working
withfuel
circuit
components
.
Thoroughly
clean
the
unionsbefore
disconnecting
fuel
fines
To
prevent
fuel
from
spraying
on
a
hotengine,
system
fuel
pressure
should
be
relieved
before
disconnecting
fuel
lines
.
One
method
is
to
tightly
wrap
a
shop
towel
around
a
fuel
line
fit-
ting
and
loosen
or
disconnect
the
fitting
.
Measuring
fuel
pressure
requires
special
tools
.
Earlier
cars
use
pressure
hose
with
clamps
for
fuel
delivery
.
These
can
be
attached
to
a
fuel
pressure
gauge
below
the
intake
manifold
.
Page 195 of 759
170
Radiator
and
Cooling
System
GENERAL
.
.
.....
.
...
.
.
.
.
.
....
.
.
.
.
.
.
.
.170-1
Coolant
Pump
and
Thermostat
........
.
.
.
.
170-1
Radiator
and
Expansion
Tank
.........
.
...
170-1
Cooling
Fans
.
....
.
.
.
.
.
.
.
.
.
.....
.
......
170-2
Warnings
and
Cautions
.
.
.
.
.
.
.
.
.
.
.
.
...
.
.
.
170-2
TROUBLESHOOTING
...
.
.
.
...
.
.
.
.
.
.
.
.
.170-2
Cooling
System
Pressure
Test
...
.
.
.
.
.
.
.
.
.
170-3
Thermostat
Quick
Check
.
.
.
.
...
.
.
.
.
.
.
.
.
.
170-3
Temperature
Gauge
Quick
Check
.
.
.
.
.
.
.
.
.
170-3
Cooling
fan,
testing
.
.
.
.
........
.
.
.
.
.
.
.
.
.
170-4
COOLING
SYSTEM
SERVICE
.
.
.
.
.
.
.
.
.
.
170-5
Coolant,draining
and
filling
.
.
......
.
.
.
.
.
..
170-5
Cooling
system,
bleeding
(radiator
with
integral
expansion
tank)
.....
170-6
GENERAL
This
section
covers
repair
and
troubleshooting
information
for
the
engine
cooling
system
.
For
heater
core
and
related
heating
and
air
conditioning
components,
see640
Heating
and
Air
Conditioning
.
Coolant
Pump
and
Thermostat
A
centrifuga¡-type
coolant
pump
is
mounted
to
the
front
of
the
engíne
.
The
belt-driven
pump
circulates
coolant
through
the
system
whenever
the
engíne
is
running
.
A
thermostat
con-
trols
the
flow
of
coolant
into
the
radiator
.
When
the
engíne
is
cold
the
thermostat
is
closed
so
coolant
bypasses
the
radiator,
recirculating
from
the
engíne
directly
back
to
the
pump
.
When
the
engíne
reaches
operating
tem-
perature,
the
thermostat
opens
and
coolant
circulates
through
the
whole
system
including
the
radiator
.
Radiator
and
Expansion
Tank
The
radiator
is
a
crossflow
design
.
A
translucent
expansion
tank
provides
for
coolant
expansion
at
higher
temperatures
and
easy
monitoringof
the
coolant
leve¡
.
On
4-cylinder
modeis,
the
radiator
expansion
tank
is
integral
with
the
radiator
.
See
Fig
.
1
.
RADIATOR
AND
COOLING
SYSTEM
170-1
Belt-driven
cooling
fan,
replacing
.
.......
.
.
.
170-7
Electric
cooling
fan,
replacing
.
.
.
.....
.
.
.
.
.
170-8
Auxiliary
cooling
fan,
replacing
.
.
.....
.
.
.
.
.
170-8
Thermostat,
replacing
.
.
.
.
.
.
.
.
.
.....
.
.
.
.
.
170-9
Coolant
pump,
replacing
..........
.
.
.
.
.
.
170-10
RADIATOR
SERVICE
.....
.
......
.
.
.
.
.
.
170-11
Radiator,
removing
and
installing
....
.
.
.
.
.
.
170-11
TABLES
a
.
Coolant
Temperature
Sensor
Wire
Colors
...
.
..
.
.
170-3b
.
Auxiliary
Cooling
Fan
Switching
Temperatures
.:.
.170-4
c
.
Auxiliary
Cooling
Fan
Temperature
Switch
Tests
..
..
.
...
...
.
.............
.
..
.
.
170-5d
.
Cooling
System
Capacities
..............
..
.
.
.
170-6
A
.
Expansion
tank
C
.
Dualtemperature
fan
switch
B
.
Radiator
drain
screw
Fig
.
1
.
Radiator
assembly
with
integral
expansion
tank
(4-cylinder
engine)
.
On
6-cylinder
models,
a
standalone
expansion
tank
is
used
.
On
cars
with
automatic
transmission,
ATF
is
circulated
through
an
additional
heat
exchanger
(ATF
cooler)
.
GENERAL
Page 197 of 759
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
Page 198 of 759
170-
4
RADIATOR
AND
COOLING
SYSTEM
A
quick
testat
the
coolant
temperature
gauge
sender
can
The
auxiliary
cooling
fan
comes
on
when
coolant
tempera
determine
if
the
gauge
is
functioning
correctly
.
ture
exceeds
a
predetermined
leve¡
or
whenever
the
air
condi-
tioning
is
on
.
A
dual-range
temperature
switch
for
cooling
fan
lf
the
gauge
needie
remains
at
the
rest
position
with
theen-
control
is
mounted
on
the
right
side
of
the
radiator
.
See
Fig
.
3
.
gine
warm,
remove
the
harness
connector
from
the
sender
and
jumper
the
correct
terminals
in
the
connector
to
simulate
a
high
engine
temperature
.
See
Table
a
.
Turn
the
ignition
on
.
If
the
gauge
needle
moves
upward,
the
sender
is
faulty
.
If
the
gauge
does
not
respond,
the
wiring
to
the
gauge
is
broken
(open
circuit)
or
the
gauge
itselfis
faulty
.
WARNING
-
1996
and
laten
models
are
OBD
11
compliant
.
Dis-
connecting
electrical
connectors
wíth
the
ignition
turned
on
may
set
fault
codes
in
the
ECM
.
It
is
rec-
ommended
that
you
leave
the
diagnosis
of
faults
in
the
coolant
temperature
sensorsystem
to
the
BMW
dealer
service
department
which
has
specialized
OBD
11
scan
tool
equipment
.
If
the
gauge
needle
reads
too
high
when
the
engine
is
cold,
remove
the
harness
connector
from
the
sender
.
Turn
the
igni-
tion
on
.
lf
the
gauge
needle
position
does
not
change,
the
wir-
ing
or
the
gauge
is
shorted
to
ground
.
If
the
gauge
needle
drops,
the
sender
is
faulty
and
should
be
replaced
.
When
re-
placing
a
faulty
coolant
temperature
sender,
the
gasket
ring
on
the
sender
should
also
be
replaced
.
Tightening
Torque
"
Temperature
gauge
sender
to
engine
18
Nm
(13
ft-Ib)
Cooling
fan,
testing
NOTE-
OnM44
engines
with
manual
transmission,
the
primary
electric
cooling
fan
is
mounted
on
the
engine
side
of
the
radiator
and
is
controlled
by
the
engine
control
module
(ECM)
.
Troubleshooting
thiscircuit
should
be
left
to
an
authorized
BMW
dealer
with
the
proper
diagnostic
equipment
An
otherwise
sound
cooling
system
may
still
overheat,
par-
ticularly
with
prolonged
idling,
due
to
a
failure
of
the
coolíng
fan(s)
.
The
belt-driven
cooling
fan
is
controlled
by
a
temperature
dependent
viscous
clutch
.
A
failed
fan
clutch
may
affect
air
flow
through
the
radiator
resulting
in
overheating
orpossibly
overcooling
.
Speed
Low
sp
High
s
With
the
engine
off,
check
thefan
clutch
by
spinning
thefan
.
eed
The
fan
should
spin
on
the
clutch
with
some
resistance
.
peed
Check
for
signs
of
leaking
fluid
from
the
clutch
.
If
thefan
free-
wheels
with
no
resistance,
cannot
be
tu
rned
by
hand,
or
there
are
signs
of
oil
leakage,
the
clutch
should
be
replaced
.
TROUBLESHOOTING
Fig
.
3
.
Radiatorcooling
fan
temperature
switch
(arrow)
.
WARNING
-
"
Use
caution
when
testing
the
electric
cooling
fan(s)
and
coolant
temperature
switch
.
Keep
hands
and
wires
clear
of
thefan
blades
.
The
cool-
ing
fan(s)
can
run
any
time
the
ignition
is
ON
.
"
For
greatest
safety,
coolíng
fan
and
coolant
tem-perature
switch
tests
shouldbe
performed
on
acoldengine
with
the
air
conditioning
off
.
Table
b
.
Auxiliary
Cooling
Fan
Switching
Temperatures
Switching
temperature
196°F(91°C)
210°F(99°C)
0012506
If
a
faulty
thermostat,
trapped
air,
or
a
restriction
in
the
sys-
tem
is
not
allowing
the
coolant
to
circulate
through
the
radia-
tor,
the
temperature
switch
will
not
close
and
the
auxiliary
cooling
fan
will
not
run
.
Before
making
the
tests
described
be-
low,
make
sure
the
thermostat
is
operating
correctly
as
de-
scribed
earlier
.
The
normal
switching
temperatures
for
the
dual
-speed
switch
are
listed
in
Table
b
.
Page 199 of 759
NOTE-
Some
cars
covered
by
this
manual
may
have
an
alter-
nate
cooling
fan
switchwith
switching
temperatures
of
176%190W
(80%88°C)
.
When
replacing
the
switch
check
theswitching
specifications,
whichshouldbe
stamped
on
the
switch
body
.
1
.
If
coolant
is
circulating
at
normal
operating
tempera-
ture,
but
auxiliary
cooling
fan
does
not
run,
disconnect
connector
from
radiator
temperature
switch
and
make
tests
listed
in
Table
c
.
Table
c
.
Auxiliary
Cooling
Fan
Temperature
Switch
Tests
Wires
jumpered
Test
Test
resuits
conditions
Black/green
(terminal2)
and
Ignition
ON
Fan
runs
on
brown
(terminal
1)
low
speed
Black/gray
(terminal
3)
and
Ignition
ON
Fan
runson
brown
(terminal
I
1)
high
speed
2
.
If
fan
runs
only
when
powered
directly
by
jumpered
connector
and
hot
coolant
is
circulating
through
radia-
tor,
radiator
temperature
switch
is
most
likelyfaulty
.
Use
a
new
sealing
ring
when
replacing
switch
Tightening
Torque
"
Temperature
switch
to
radiator
......
15
Nm
(11
ft-Ib)
3
.
If
auxiliary
fan
does
notrun
when
powered
directly,
check
for
battery
voltage
at
temperature
switch
connec-
tor
(black/green
wire)
with
ignition
on
.
If
battery
voltage
is
not
present,
check
fuses
.
See
610
Electrical
Com-
ponent
Locations
.
RADIATOR
AND
COOLING
SYSTEM
170-
5
~r~nmm
a
00
0
Fig
.
4
.
Auxiliary
radiator
cooling
fan
low
speed
relay
(1)
and
high
speed
relay
(2)
in
power
distribution
box
.
(Relay
locations
may
vary
.)
Auxiliary
Cooling
Fan
Circuit
Fuses
Fig
.
5
.
Auxiliary
radiator
fan
resistor
(arrow)
.
"
Fuse16
.
...................
..
..
...
...
.5
amp
"
Fuse
41
(ex
.
M44
w/man
.
trans)
.
..
.
..
.....
30
amp
"
Fuse
48
(M44
w/man
.
trans
.
only)
..
.
..
.....
40
amp
COOLING
SYSTEM
SERVICE
0013034
4
.
If
no
faults
are
found,
remove
low
speed
relay
and
turn
Coolant,draining
and
filling
ignition
ON
.
See
Fig
.
4
.
1
.
Remove
expansion
tank
cap
.
Set
temperature
controls
"
Check
for
power
at
terminal
30
and
terminal
86
of
relay
to
full
warm
.
socket
.
"
Reinstall
low
speed
relay
and
repeat
testat
high
speed
WARNING
-
relay
socket
.
Fix
any
wiring
faults
found
.
Allow
the
cooling
system
to
cool
before
openlng
or
On
early
productioncars
(up
to
9/92)
:
If
fan
operates
only
on
draining
the
cooling
system
.
high
speed
and
no
electrical
faults
have
been
foundup
to
this
point,
usean
ohmmeter
to
check
that
fan
resistor
is
not
electri-
2
.
Place
3
ra
allo
ug
.
beneath
radiator
drain
plug
and
re-
cally
open
.
Resistor
is
mounted
on
auxiliary
cooling
fan
housing
move
drain
plg
.
See
Fig
.
6
.
behind
front
grille
.
See
Fig
.
5
.
Wiring
diagrams
for
the
radiator
cooling
fan
canbefoundunder
Electrical
Wiring
Diagrams
.
3
.
Place
3-g
pail
beneath
rear
of
engine
blo
.
Loos-
en
and
re
mlon
ove
engine
blockcoolant
drain
plug
k
.
COOLING
SYSTEM
SERVICE
Page 203 of 759
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