1992 BMW M3 radiator cap
[x] Cancel search: radiator capPage 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 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 381 of 759
600
Electrical
System-General
GENERAL
.
...........
.
.
.
.
.
.
.
.
.
...
.
...
600-1
Voltage
and
Polarity
........
.
.
.
.
.
.
.
.....
600-1
Ming,
Fuses
and
Relays
............
.
.
.
.
600-1
Electrical
System
Safety
Precautions
...
.
.
.
.
600-1
Electrical
Test
Equipment
.....
.
.
.
....
.
.
.
.
600-2
WIRING
DIAGRAMS
..
.
.
.
.
.
.
.
.
.
........
600-2
Ming
Codes
and
Abbreviations
..
.
...
.
....
600-2
ELECTRICAL
TROUBLESHOOTING
..
.
..
600-3
Voltage
and
Voltage
Drops
..........
.
.
.
.
.
600-4
GENERAL
Electrical
System
Safety
Precautions
A
brief
description
of
the
principal
parts
of
the
electrical
sys-
tem
is
presented
here
.
Also
covered
here
are
basic
electrical
system
troubleshooting
tips
.
Voltage
and
Polarity
The
vehicle
electrical
system
is
a
12-volt
direct
current
(DC)
negative-ground
system
.
A
voltage
regulator
controls
system
voltage
at
approximately
the
12-volt
rating
of
the
battery
.
Al¡
circuits
are
grounded
by
direct
or
indirect
connection
to
the
negative
(-)
terminal
of
the
battery
.
A
number
of
ground
con-
nections
throughout
the
car
connect
the
wiring
harness
to
chassis
ground
.
These
circuits
are
completedby
the
battery
cable
or
ground
strap
between
the
body
and
the
battery
nega-
tive
(-)
terminal
.
Wiring,
Fuses
and
Relays
Nearly
all
parts
of
the
wiring
harnessconnect
to
compo-
nents
of
the
electrical
system
with
keyed,
push-on
connectors
that
lock
into
place
.
Notable
exceptions
arethe
heavy
battery
cables
and
the
starter
wiring
.
The
wiring
is
color-coded
for
cir-
cuitidentification
.
With
theexception
of
the
battery
charging
system,
most
electrical
power
is
routed
from
the
ignition
switch
or
the
bat-
tery
through
the
main
fuse/relay
panel,
located
in
¡he
left
rear
comer
of
the
engine
compartment
.
Fuses
are
color
coded
to
indicate
current
capacities
.
The
relays
and
control
units/modules
are
mounted
in
vari-
ous
places
throughout
the
vehicle
.
See610
Electrical
Com-
ponent
Locations
.
ELECTRICAL
SYSTEM-GENERAL
600-1
Voltage,
measuring
.
.
.
................
.
.
600-4
Voltage
drop,
testing
.
.
.....
.
.....
.
......
600-4
Continuity,
checking
..
.
...
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
600-5
Short
Circuits
.
.
.
.
.
.
.
.
.....
.
...
.
.
.
.
.
.
.
.
.
600-5
Short
circuit,
testing
with
ohmmete'r
.
.
.
.
.
.
.
.
.
600-6
Short
circuit,
testing
with
voitmeter
.
.
.
.
.
.
.
.
.
600-6
TABLES
a
.
Terminal
and
Circuit
Numbers
..............
..
.600-3
Please
read
the
following
warnings
and
cautions
before
do-
ing
any
work
on
your
electrical
system
.
WARNING
-
"
The
cars
covered
by
this
manual
are
equipped
with
aSupplemental
Restraint
System
(SRS)
that
automatically
deploys
one
or
more
airbags
.
Each
airbag
unit
houses
an
explosive
powerful
charge
.
Any
work
involving
the
SRS
system
should
only
be
performed
byan
authorized
BMW
dealer
.
Making
repairs
without
the
proper
knowledge
and
special
test
equipment
may
cause
serious
per-
sonal
injury
.
See
721
Airbag
System
(SRS)
.
"
The
ignition
system
of
the
car
operates
at
lethal
voltages
.
People
with
pacemakers
or
weak
hearts
should
not
expose
themselves
to
the
ignition
sys-
tem
.
Extra
caution
mustbe
taken
when
working
on
the
ignition
system
or
when
servicing
theen-
gine
while
it
is
runningor
the
key
is
on
.
See
120
Ignition
System
for
additional
ignition
system
warnings
and
cautions
.
"
Before
operating
the
starter
without
starting
the
engine
(as
when
making
a
compressfon
test),
dis-
able
the
ignition
system
as
described
in
120
Igni-
tion
System
.
"
Keep
hands,
clothing
and
other
objects
clear
of
the
electric
radiator
coollng
fan
when
working
on
a
warm
engine
.
The
fan
may
start
at
any
tíme,
even
when
the
ignition
is
switched
off
.
GENERAL