coolant temperature BMW 328i 1995 E36 Owner's Manual
Page 179 of 759
Table
j.
ECM
Pin
Assignment-Bosch
DME
M3
.3
.1
Pin
~
Signal
1
Componentffunction
1
signal
FUEL
INJECTION
130-
33
45
ground
Ignition
circuit
shield
Ground
shieldfor
ignition
circuit
monitoring
46
output
Fuel
consumption
(KVA
signal)
To
instrument
cluster
47
output
Crankshaft
rpm
Engine
speed
(TD)
signal
to
instrument
cluster
48
output
A/C
compressor
control
A/C
compressor
relay
terminal
85
49
vacant
-
-
50
output
Ignition
coil
control,
cyl
.
1
Primary
signal,
ignition
coil
1
51
output
Ignition
coil
control,
cyl
.
2
Primary
signal,
ignition
coil
2
52
output
Ignition
coil
control,
cyl
.
3
Primary
signal,
ignition
coil
3
53
vacant
-
-
54
input
Power
supply
Battery
voltagefrom
main
relay
(terminal
87a)
55
ground
Ground
Ground
for
ignition
control
56
input
Power
supply
(terminal15)
Batteryvoltage
with
key
on
or
engine
running
57
input
Ignition
timing
intervention
From
A/T
control
module
58
vacant
-
-
59
output
Throttleposition
sensor
(TPS)
Voltage
supply
to
TPS
(5
VDC)
60
input
Programming
voltage
Data
link
connector
61
vacant
-
-
62
vacant
-
-
63
vacant
-
-
64
input
A/C
on
signal
From
integrated
climate
control
module
65
input
A/C
pressure
signal
From
integrated
climate
control
module
via
A/C
pressure
switch
66
input
On-board
computer
Drive-away
protection
enable
(starter
immobilization
relay)
67
vacant
-
-
68
vacant
-
-
69
input
Knock
sensor
#2
(cyl
.
4,5,
6)
Knock
sensor
#2
signal
70
input
Knock
sensor
#1
(cyl
.
1,2,
3)
Knock
sensor
#1
signal
71
ground
Ground
Ground
for
knock
sensors
and
shields
72
vacant
-
-
73
input
Throttleposition
sensor
(TPS)
Throttleposition
signal
74
vacant
-
75
vacant
-
-
76
vacant
-
77
input
Intakeair
temperatura
Intakeair
temperatura
sensor
(0-5
VDC)
78
input
Engine
coolant
temperature
Engine
coolant
temperature
sensor
(0-5
VDC)
79
vacant
-
80
vacant
-
-
81
input
Automatic
transmission
gear
positionlneutral
A/T
parkor
neutral
position
signal
safetyswitch
82
vacant
-
-
83
vacant
-
-
84
vacant
-
-
85
vacant
-
-
86
vacant
-
-
87
input
Diagnostic
connector
(RxD)
Diagnostic
RxD
(receive)
signal
to
pin
15
in
Data
link
connector
88
input/output
Diagnostic
connector
(TxD)
Diagnostic
TxD
(transmit)
signal
to
pin
20
in
Data
link
connector
ECM
PIN
ASSIGNMENTS
Page 181 of 759
Table
k
.
ECM
Pin
Assignment-Bosch
DME
M5
.2
(continued)
Pin
I
Signal
1
Componentltunction
1
Signal
45
I
output
I
Mass
air
flow
meter
I
Intake
airSignal
46
output
Oxygen
sensor
(monitoring
sensor)
Oxygen
sensor
control
47
not
used
-
48
not
used
-
49
output
Ignition
coil
control,
cyl
.
1
Primary
signal,
ignition
coil
1
50
output
Ignition
coil
control,
cyl
.
2
Primary
signal,
ignition
coil
2
51
not
used
-
52
not
used
-
53
input
Throttleposition
sensor
Throttleposition
Signal
54
input
Power
supply
Batteryvoltage
from
main
relay
(terminal
87)
55
ground
Ground
Ground
for
ECM
56
input
Power
supply
(terminal
15)
Battery
voltage
with
key
on
or
engine
running
57
output
Activate
cooling
fan
(man
.
trans
.)
control
Normal
speed
relay
58
not
used
-
-
59
not
used
-
-
60
input
Programming
voltage
Programming
voltage
via
data
link
connector,
pin
18
61
output
Evaporative
emissionvalve
Evaporative
emission
valve
control
62
vacant
-
-
63
output
Fuel
pump
relay
Fuel
pump
relay
control
64
not
used
-
65
not
used
-
-
66
not
used
-
-
67
not
used
-
-
68
input
Signal
above
80°C(man
.
tran
.)
Double
temperature
switch
69
input
Automatic
climate
control
Automatíc
climate
control
70
input
Knock
sensor
#1
(cyl
.
1,2)
Knock
sensor
#1
Signal
71
ground
Ground
Ground
for
analog
signals
and
knock
sensors
72
not
used
-
-
73
not
used
-
-
74
input
Engine
coolant
temperature
sensor
Engine
coolant
temperatura
Signal
75
not
used
-
-
76
not
used
-
-
77
output
Oxygen
sensor
(regulating
sensor)
Oxygen
sensor
control
78
input
Crankshaft/rpm
sensor
Crankshaft
position/rpmSignal
79
input
ABS
or
traction
control
ABS
or
AST
control
80
input
Engine
speed
Engine
speed
Signal
81
not
used
-
-
82
not
used
-
-
FUEL
INJECTION
130-
3
5
83
input
On-board
computar
From
On-boardcomputer
(terminal
4)
84
not
used
-
-
85
not
used
-
-
86
not
used
-
-
87
input
Diagnostic
connector
(RxD)
Diagnostic
RxD
(receive)signal
to
pin
15
in
Data
link
connector
88
output
I
Diagnostic
connector
(TxD)
Diagnostic
TxD
(transmit)
signal
to
pin
17in
Data
link
connector
ECM
PIN
ASSIGNMENTS
Page 182 of 759
130-
3
6
FUEL
INJECTION
Pin
1
Signal
1
Componentffunction
1
Signal
1
output
Ignition
coil
control,
cyl
.
2
Primary
signal,
ignition
coil
2
2
output
Ignition
coil
control,
cyl
.
4
Primary
signal,
ignitioncoil
4
3
output
Ignition
coil
control,
cyl
.
6
Primary
signal,
ignition
coil
6
4
ground
Ground
Ground
5
output
Fuel
injectorcontrol,
cyl
.
2
Pulsed
ground
(injection
pulse
width
in
ms)
cyl
.
2
6
output
Fuel
injectorcontrol,
cyl
.
1
Pulsed
ground
(injection
pulse
width
in
ms)
cyl
.
1
7
output
Mass
air
flow
meter
Mass
air
meter
signal
8
input
Mass
air
flow
meter
Mass
air
meter
signal
9
output
Instrument
cluster
Fuel
consumption
signal
10
output
Engine
coolant
temperature
(ECT)
sensor
ECT
signal
11
output
Fueltankpressure
sensor
Fueltankpressure
sensor
control
12
input
Throttleposition
sensor
(TPS)
Throttleposition
signal
13
-
14
input
Intake
air
temperature
(IAT)
sensor
Intake
air
temperature
signal
15
Traction
control
AST
module
16
input
Automatic
climate
control
Automatic
climate
control
17
18
input
Electronic
immobilizer
control
(EWS
II)
Electronic
immobilizer
control
(EWS
II)
module
19
Automatic
climate
control
Automatic
climate
control
20
-
Instrument
cluster
Instrument
cluster
21
output
Camshaft
actuator
(VANOS
solenoid)
control
Camshaft
actuator
(VANOS
solenoid),
switched
ground
22
output
Fuel
injectorcontrol,
cyl
.
3
Pulsed
ground
(injection
pulse
width
in
ms)
cyl
.
3
23
Fuel
injectorcontrol,
cyl
.
6
Pulsed
ground
(injection
pulse
width
in
ms)
cyl
.
6
24
Fuel
injectorcontrol,
cyl
.
4
Pulsed
ground
(injection
pulse
width
in
ms)
cyl
.
4
25
output
Oxygen
sensor
heater
control
Oxygen
sensor
heater
ground
26
input
Power
supply
(terminal
30)
Battery
voltage(B+)
at
all
times
27
output
Idle
speed
control
valve
Pulsed
ground-open
signal
(see
also
pin
53)
28
ground
Ground
Ground
29
output
Ignition
coil
control,
cyl
.
1
Primary
signal,
ignition
coíl
1
30
output
Ignition
coil
control,
cyl
.
3
Primary
signal,
ignition
coil
3
31
output
Ignition
coil
control,
cyl
.
5
Primary
signal,
ignition
coil
5
32
ground
Ground
Ground
33
output
Fuel
injector
control,
cyl
.
5
Pulsedground
(injection
pulsewidth
in
ms)
cyl
.
5
34
ground
Ground
Ground
35
output
Secondary
air
injection
Secondary
air
injection
pump
relay
control
36
output
Engine
speed
output
Engine
speed
signal
37
-
38
ground
Knock
sensor
Shielding
for
knock
sensors
39
output
Intake
air
temperature
sensor
(IAT
Sensor)
Voltagesupply
to
IAT
sensor
and
ECT
sensorEngine
coolant
temperature
(ECT)
sensor
40
output
Crankshaft
position
sensor
(Hall
effect)
Crankshaft
position
sensor
control
41
ground
Camshaft
position
(CMP)
sensor
Shielding
for
CMP
sensor
42
output
Throttle
position
sensor
(TPS)
TPS
ground
43
input
Camshaft
position/rpm
sensor
Camshaft
position/rpm
sensor
control
44
output
Throttle
position
sensor
(TPS)
Voltagesupply
to
TPS
(5
VDC)
45
Traction
control
AST
module
46
-
Instrument
cluster
Instrument
cluster
ECM
PIN
ASSIGNMENTS
Table
I.
ECM
Pin
Assignment-Siemens
DME
MS
41
.1
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 196 of 759
170-2
RADIATOR
AND
COOLING
SYSTEM
Cooling
Fans
TROUBLESHOOTING
Belt-driven
coolingfan
.
The
primary
cooling
fan
is
belt-
driven
.
It
is
mounted
to
the
frontof
the
coolant
pump
through
a
fan
clutch
.
The
fan
clutch
is
a
viscous
fluid
coupling
that
con-
trols
the
speed
of
thefan
based
on
engine
compartment
tem-
perature
.
Electric
cooling
fan
.
Models
with
M44
engine
and
stan-
dard
transmission
substitute
an
electric
fan
for
the
belt-driven
viscous
fan
.
This
is
attached
to
the
rear
of
the
radiator
and
controlledvia
the
DME
5
.2
engine
management
system
.
NOTE-
The
electric
cooling
fan
in
these
models
is
activated
by
the
engine
control
module
(ECM)
.
Auxiliary
coolingfan
.
In
al¡
models
a
two-speed
electric
auxiliary
cooling
fan
is
mounted
behind
the
front
grill
and
in
front
of
the
radiator
.
This
fan
is
primarily
used
for
the
A/C
sys-
tem,
but
also
operates
when
the
coolant
temperature
ex-
ceeds
a
predetermined
leve¡
.
Warnings
and
Cautions
The
following
warnings
and
Cautions
should
beobserved
when
working
on
the
cooling
system
.
WARNING
-
"
Atnormal
operating
temperature
the
cooling
sys-
tem
is
pressurized
.
Allow
the
system
to
cool
as
long
as
possible
before
opening-a
minimum
of
an
hour-then
release
the
cap
slowly
to
allow
sale
release
of
pressure
.
"
Releasing
the
cooling
system
pressure
lowers
the
coolants
boiling
point
and
the
coolant
may
boíl
suddenly
.
Use
heavy
gloves
and
wear
eye
and
laceprotection
to
guard
against
scalding
.
"
Use
extreme
care
when
draining
and
disposing
of
engine
coolant
.
Coolant
is
poisonous
and
lethal
to
humans
and
pets
.
Pets
are
attracted
to
coolant
because
of
its
sweet
smell
and
taste
.
Consult
a
veterinarian
immediately
if
coolant
is
ingested
byan
animal
.
CAUTION-
"
Avoidadding
cold
water
to
the
coolant
while
the
engine
is
hot
or
overheated
.
If
it
is
necessary
to
add
coolant
to
ahot
system,
do
so
only
with
the
engine
running
and
coolant
pump
tuming
.
"
Prior
to
disconnecting
the
battery,
read
the
bat-
tery
disconnection
cautions
given
at
the
front
of
this
manual
on
page
viii
.
TROUBLESHOOTING
Most
cooling
system
faults
can
be
grouped
into
one
of
three
categories
:
"
Cooling
system
leaks
"
Poor
coolant
circulation
"
Radiator
cooling
fan
faults
When
investigating
the
cause
of
overheating
or
coolant
loss,
begin
with
a
visual
inspection
.
Be
sure
to
check
the
con-
dition
and
tension
of
the
coolant
pump
drive
belt
.
Check
hoses
for
cracks
or
softness
.
Check
clamps
for
looseness
.
Check
the
coolant
leve¡
and
check
for
evidence
of
coolantleaks
from
the
engine
.
Check
that
the
radiator
fins
are
not
blocked
with
dirt
or
de-
bris
.
Clean
the
radiator
using
low-pressure
water
or
com-
pressed
air
.
Blow
outward,
fromthe
engine
side
out
.
Inspect
the
coolant
pump
by
first
removing
the
drive
belt
from
the
pump
.
Firmly
grasp
opposite
sídes
of
the
pulley
and
check
for
play
in
all
directions
.
Spin
the
pulley
and
check
that
the
shaft
runs
smoothly
.
NOTE-
The
coolant
provides
lubrication
for
the
pump
shaft,
soan
occasional
drop
of
coolant
leaking
from
the
pump
is
acceptable
.
If
coolant
drips
steadily
from
the
vent
hole,
the
pump
should
be
replaced
.
The
cooling
system
becomes
pressurized
at
normal
operat-
ing
temperature,
which
raises
the
boiling
point
of
the
coolant
.
Leaks
may
prevent
the
system
from
becoming
pressurized,
allowing
the
coolant
to
boil
at
a
lower
temperature
.
If
visual
ev-
idence
is
inconclusive,
a
cooling
system
pressure
test
can
help
to
pinpointhard-to-find
leaks
.
If
the
cooling
system
is
full
of
coolant
and
holds
pressure,
the
next
most
probable
cause
of
overheating
are
:
"
Faulty
radiator
fan
"
Loose
or
worn
drive
belt
"
Failed
thermostat
or
coolant
pump
"
Clogged/plugged
radiator
or
coolant
passages
.
NOTE
-
"
Some
early
style
coolant
pumps
were
fitted
wíth
fi-
berlplastic
type
impellers
.
Over
time,
this
impeller
can
wear
away
and
result
in
overheating
.
The
plastic
im-
peller
can
also
slip
or
free-wheel
on
the
pump
shaft
.
If
the
engine
overheats
and
no
other
faults
canbe
found,
theold
style
impeller
may
be
the
cause
of
the
problem
.
"
Only
pumps
with
the
updated
metal
impeller
should
be
used
for
replacement
.
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 200 of 759
170-6
RADIATOR
AND
COOLING
SYSTEM
Fig
.
6
.
Radiator
drain
plug
(arrow)
.
WARNING
-
Coolant
is
poisonous
.
Itis
especially
lethal
to
pets
.
Cleanup
spills
immediately
and
rinse
the
area
with
water
.
NOTE
-
The
block
drain
plug
is
located
on
the
exhaust
side
of
the
engine,
near
the
reas
of
the
engine
.
4
.
Reinstall
radiator
and
engine
block
drain
plugsusing
new
sealing
washers
.
Leave
heater
controis
on
full
warm
.
5
.
Using
a
coolantmixture
of
50%
antifreeze
and
50%
dis-
tilled
water,
fill
system
slowly
On
radiator
with
integral
expansion
tank,
bleed
cooling
system
as
described
be-
low
.
NOTE-
"
Tap
water
may
cause
corrosion
of
radiator,
engine
and
coolant
hoses
.
"
Coolant
can
often
be
reused
provided
itis
clean
and
less
than
twoyears
old
.
Do
not
reuse
coolant
when
re-
placing
damaged
engine
parts
.
Contaminated
coolant
may
damage
the
engine
or
cooling
system
.
Tabled
.
Cooling
System
Capacities
Engine
j
Capacity
4-cylinder
1
6
.5
liters
(6.9
qt)
6-cylinder
M50/M52
10
liters
(10
.6
qt)
S50US/S52US
10
.5
liters
(11
.1
qt)
COOLING
SYSTEM
SERVICE
Tightehing
Torques
"
Radiator
drain
plug
to
radiator
...
2-3
Nm
(18-27
in-lb)
"
Engine
block
drain
plug
to
block
.
.
..
25
Nm
(18
ft-Ib)
Cooling
system,
bleeding
(radiator
with
integral
expansion
tank)
NOTE
-
On
radiators
with
a
separate
expansion
tank,
ableed
screw
is
not
provided
.
The
cooling
system
with
sepa-
rate
expansion
tank
is
self
bleeding
via
the
vent
hose
on
the
expansion
tank
.
Air
maybecome
trapped
in
the
system
during
filling
.
Trapped
air
can
prevent
proper
coolant
circulation
.
Whenever
the
coolant
is
drained
and
filled,
the
system
should
be
bled
of
trapped
air
.
1
.
With
engine
cold,
add
coolant
to
expansion
tank
until
level
reaches
COLD
(KALT)
mark
on
tank
.
2
.
Loosen
bleed
screw
on
radiator
expansion
tank
.
See
Fig
.
7
.
0011976
Fig
.
7
.
Cooling
system
bleed
screwon
radiator
(arrow)
.
Note
cold
level
mark
on
expansion
tank
.
3
.
M3
models
:
Loosen
bleed
screw
on
thermostathous-
ing
.
4
.
Set
temperature
controls
in
passenger
compartment
to
fui¡
warm
and
turn
ignition
on
position
(do
not
start
en-
gine)
.
Page 201 of 759
5
.
Slowly
add
coolant
until
it
spills
from
bleed
screws
.
When
coolant
spillíng
from
bleed
screws
is
free
of
air
bubbies,
tighten
screws
.
6
.
Run
engine
until
it
reaches
operatíng
temperature
.
Af-
ter
engine
has
cooled,
recheck
coolant
level
and
top
up
as
necessary
.
CAUTION-
Always
use
genuine
BMW
coolant
or
its
equiva-
lent
to
avoid
the
formation
of
harmful,
clogging
de-
posits
in
the
cooling
system
.
Use
of
other
antifreeze
solutions
may
be
harmful
to
the
cooling
system
.
Tightening
Torque
"
Radiator
bleed
screw
to
thermostat
housing
...
.
.
........
8
Nm
(71
in-lb)
Belt-driven
cooling
fan,
replacing
1
.
Usinga32
mm
wrench
on
fan
clutch
nut,
turn
wrench
quickly
in
a
clockwise
direction
(working
from
front
of
car)
to
loosen
.
Spin
fan
off
pump
.
See
Fig
.
8
.
NOTE-
"
The
radiator
cooling
fan
nut(32
mm
wrench)
has
left-
hand
threads
.
"
The
nut
may
be
difficult
to
loosen
.
Use
a
tool
to
hold
the
coolant
pump
pulleystationary
.
BMW
hasa
spe-
cial
tool
forthis
purpose
(BMW
special
tool
no
.
115
030)
.
2
.
Remove
expansion
rivets
holding
shroud
to
radiator
.
See
Fig
.
9
.
Remove
fan
and
shroud
together
.
NOTE-
Store
the
removed
fan
clutch
assembly
in
an
upright
(installed)
positionto
prevent
lossof
clutch
fluid
.
RADIATOR
AND
COOLING
SYSTEM
170-
7
Fig
.
8
.
Radiatorcooling
fannut
(arrow)
.
Nuthas
left-hand
threads
.
3
.
To
replace
fan
clutch,
remove
fan
mounting
bolts
and
separate
clutch
from
fan
.
Fig
.
9
.
Fan
shroud
retaining
rivet
(arrow)
.
Pryout
center
pin
and
re
4
.
Installation
is
reverse
of
rernoval
.
move
rivet
.
Rivet
design
may
vary
depending
on
model
and
model
year
.
Tightening
Torques
"
Clutchnut
to
coolant
pump
(left-hand
threads)
Wíthout
BMW
tool
no
.
11
5
040
.....
40
Nm
(29
ft-lb)
With
BMW
tool
no
.
11
5
040
.
......
30
Nm
(22
ft-Ib)
"
Fan
to
viscous
clutch
...
.
..
.
......
10
Nm
(89
in-lb)
0013203
COOLING
SYSTEM
SERVICE