1994 BMW 325i temp

130-
3
2



FUEL
INJECTION

Pin



1
Signal



1
Component/function



1
Signal

1



output



Fuel
pump
relay
control



Fuel
pump
relay
switches
with
engine
running
or
cranking
(crankshaft
position
signal
must
be
present
for
relay
switchover)

2



output



Idle
speed
control
valve



Pulsed
ground-close
signal
(seealso
pin
29)

3



output



Fuel
ínjectorcontrol,
cyl
.
5



Pulsed
ground
(injection
pulsewidth
in
ms)
cyl
.
5
4



output



Fuel
injectorcontrol,
cyl
.
6



Pulsed
ground
(injection
pulsewidth
in
ms)
cyl
.
6
5



output



Fuel
injectorcontrol,
cyl
.
4



Pulsed
ground
(injection
pulsewidth
in
ms)
cyl
.
4
6



ground



Ground



Ground
for
fuel
injector
output
stage

7



output



Camshaft
actuator
(VANOS
solenoid)
control



Camshaft
actuator
(VANOS
solenoid)

8



output



Check
Engine



Instrument
cluster,
Check
Engine
lamp

9
vacant
-



-

10
vacant
-



-

11



output



Throttle
position



Throttle
angle
signal
to
A/T
control
module
12
vacant
-



-

13



input



Oxygen
sensor



Oxygen
sensor
signal
(0-1
VDC
fluctuating
with
engine
running)

14



input



Mass
air
flow
sensor



Mass
air
flow
sensor

15
ground
Ground



Ground

16



input



Crankshaft
position/rpm
sensor



Voltage
pulse
(VAC)
between
pin
16
and
43
(crank
position/rpm
sensor)

17



input



Camshaft
position
sensor



Halleffect
camshaft
sensor

18
vacant
-



-

19
vacant
-



-

20
vacant
-



-

21
vacant
-



-

22
vacant
-



-

23



output



Ignition
coil
control,
cyl
.
4



Ignition
coil
4

24



output



Ignition
coil
control,
cyl
.
6



Ignition
coil
6

25



output



Ignition
coil
control,
cyl
.
5



Ignition
coil
5

26



input



Power
supply
(terminal
30)



Battery
voltage(B+)
at
all
times

27



input



Main
relay
control



Main
relayactivation
(terminal
85)

28



ground



Ground



Ground
for
ECM
and
sensor
shielding

29



output



Idle
speed
control
valve



Pulsed
ground-open
signal
(seealsopin
2)

30
vacant
-



-

31



output



Fuel
injectorcontrol,
cyl
.
3



Injection
pulse
wicith
in
ms-cyl
.
3

32



output



Fuel
injectorcontrol,
cyl
.
2



Injection
pulse
wicith
in
ms-cyl
.
2

33



output



Fuel
injectorcontrol,
cyl
.
1



Injection
pulsewidth
in
ms-cyl
.
1

34



ground



Ground



Ground
for
remaining
output
stages

35
vacant
-



-

36



output



Evaporative
purge
valve
control

37
vacant
-



-

38



output



Oxygen
sensor
heater
relay
control



Oxygen
sensor
heater
relay
switchover
(terminal
85)

39
vacant
-



-

40



ground



Oxygen
sensor



Oxygen
sensor
signal
ground

41



input



Mass
air
flow
sensor



Mass
air
flow
voltage
signal

42



input



Vehicle
speed



Vehicle
speed
signal
from
instrument
cluster

43



input



Crankshaft
position/rpm
sensor



Voltage
pulse
(VAC)
between
pin16
and
43
44



ground



Ground



Ground
for
intake
air
temp
.
sensor,
engine
coolant
temp
.
sensor,
throttle
position
sensor

ECM
PIN
ASSIGNMENTS

Table
j
.
ECM
Pin
Assignment-Bosch
DME
M3
.3
.1

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

130-
34



FUEL
INJECTION

Pin



i
Signal



1
Component/function



1
Signal

1



output



Oxygen
sensor
(monitoring
sensor)heater



Oxygen
sensor
heater
control
(switched
ground)

2



output



Idle
speed
control
valve



Pulsed
ground-close
signal
(see
also
pin
29)

3



output



Fuel
injector
control,
cyl
.
1



Pulsed
ground
(injection
pulsewidth
in
ms)
cyl
.
1

4



output



Fuel
injector
control,
cyl
.
4



Pulsed
ground
(injection
pulse
width
in
ms)
cyl
.
4

5



not
used



-



-

6



ground



Ground



Ground
for
fuel
injector
output
stage

7



not
used



-

8



1
output



1
Check
Engine



1
Instrument
cluster,
Check
Engine
lamp

9



not
used



-



-

10



input



Electronic
immobilizer
control
(EWS
II)



Electronic
immobilizer
control
(EWS
II)
module

11



output



Automatic
climate
control



Automatic
climate
control,
to
evaporator
controlier

12



not
used



-



-

13



not
used



-



-

14



not
used



-



-

15



not
used



-



-

16



input



Intake
air
temperature



Intake
air
temperature
Signal

17



input



Mass
air
flow
meter



Intake
air
signal

18



not
used



-



-

19



input



Oxygen
sensor
(monitoring
sensor)



Oxygen
sensor
control

20



output



Crankshaft/rpm
sensor



Crankshaft/rpm
sensor
control

21



input



Camshaft
position
sensor



Camshaft
position
signal

22



output



Ignition
coil
control,
cyl
.
3



Primary
signal,
ignitioncoil
3

23



output



Ignition
coil
control,
cyl
.
4



Primary
signal,
ignitioncoil
4

24



not
used



-



-

25



not
used



-



-

26



input



Power
supply
(terminal
30)



Battery
voltage
(B+)
at
al¡
times

27



input



Main
relay
control



Main
relay
activation
(terminal
85)

28



ground



Ground



Ground
for
ECM
and
sensor
shielding

29



output



Idle
speed
control
valve



Pulsed
ground-open
signal
(seealsopin
2)

30



output



Oxygen
sensor
(monitoring
sensor)
heater



Oxygen
sensor
heater
control
(switched
ground)

31



output



Fuel
injectorcontrol,
cyl
.
3



Pulsed
ground
(injection
pulsewidth
in
ms)
cyl
.
3

32



output



Fuel
injector
control,
cyl
.
2



Pulsed
ground
(injection
pulsewidth
in
ms)
cyl
.
2

33



I
not
used

40



input



Knock
sensor
#2
(cyl
.
3,4)



Knock
sensor
#2
signal

41



not
used



-



-

42



input



Vehicle
speed



Vehicle
speed
signal
from
instrument
cluster

43



not
used



-



-

44



output



Throttleposition
sensor
(TPS)



Throttleposition
reference
signal

ECM
PIN
ASSIGNMENTS

Table
k
.
ECM
Pin
Assignment-Bosch
DME
M5
.2

34



ground



Ground



Ground
for
ECM/
output
stages

35



not
used



-



-

36



input



A/C
compressor
relay



A/C
compressor
relay
control

37



not
used



-



-

38



not
used



-



-

39



not
used



-



-

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

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

Table
I
.
ECM
Pin
Assignment-Siemens
DME
MS
41
.1
(continued)

Pin



I
Signal



I
Component/function



1
Signal

FUEL
INJECTION



130-
37

47
-

48



input



Crankshaft
position
sensor
(Hall
effect)



Crankshaft
position
sensor
control

49



input



Power
supply
(terminal
15)



Batteryvoltage
with
key
onor
engine
running
50



output



Solenoid
valve
(running
losses)



Running
losses

51



output



Carbon
canister
valve



Carbon
canister
valve
control

52vacant
-

53



output



Idle
speed
control
valve



Pulsed
ground-close
signal
(seealsopin29)
54



input



Power
supply



Battery
voltagefrom
main
relay
(terminal
87)

55
vacant
-

56
-

57



input



Knock
sensor
(cyl
.
1-3)



Knock
sensor
input
Signal

58



output



Knock
sensor
(cyl
.
1-3)



Knock
sensor
control

59



input



Knock
sensor
(cyl
.
4-6)



Knock
sensor
input
Signal

60



input/output



Diagnostic
connector
(TxD)



Diagnostic
TxD
(transmit)
signal
to
pin
18
in
Data
link
connector
61



output



Oxygen
sensor
heater
(monitoring
sensor)



Oxygen
sensor
heater
ground

62



output



Secondary
air
injection



Secondary
air
injection
control
valve

63



output



Knock
sensor
(cyl
.
4-6)



Knock
sensor
control

64



input



Camshaft
position/rpm
sensor



Camshaft
position/rpm
sensor
control

65



input



Camshaft
position/rpm
sensor



Camshaft
position/rpm
sensor
control

66
-

67



output



Oxygen
sensor



Oxygen
sensor
reference
voltage

68



output



Evaporative
purge
valve
control



Pulsed
ground
with
engine
at
normal
temperature
and
varyingengine
load

69



output



Fuel
pump
relay
control



Fuel
pump
relay
switches
with
engine
runningorcranking
(crankshaft
position
signal
must
be
present
for
relay
switchover)

70
vacant
-



-

71



output



Oxygen
sensor
heater
(regulating
sensor)



Oxygen
sensor
heater
ground

72



output



Oxygen
sensor
(monitoring
sensor)



Oxygen
sensor
referencevoltage

73



input



Main
relay
control



Main
relay
activation
(terminal
85)

74



output



A/C
compressor
control



A/C
compressor
relay
control

75



input



Oxygen
sensor



Oxygen
sensor
signal

76



not
used



-



-

77



input



Oxygen
sensor
(regulating
sensor)



Oxygen
sensor
signal

78



input



Oxygen
sensor
(monitoring
sensor)



Oxygen
sensor
signal

79



output



Oxygen
sensor
(regulating
sensor)



Oxygen
sensor
referencevoltage

80



Traction
control



AST
module

81



Traction
control



AST
module
82



Traction
control



AST
module
83



output



Crankshaft
position
sensor
(Hall
effect)



Crankshaft
position
sensor
control

84
vacant
-



-

85



output



Automatic
transmission



Automatic
transmission
control
module

86



input



Automatic
transmission



Automatic
transmissíon
control
module

87



input



Power
supply



Battery
voltage
from
main
relay
(terminal
87)

88



input/output



Diagnostic
connector
(TxD)



Diagnostic
TxD
(transmit)
signal
to
pin
17
in
Data
link
connector

ECM
PIN
ASSIGNMENTS

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

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
.