coolant temperature JAGUAR X308 1998 2.G User Guide

Engine Cooling
- Engine Cooling
Descr
i
ption and Operation
Engine Cooling Comp onents - Normally Aspirated Vehicles

Engine cooling is via a low volume, high velocity system which achieves a very fast warm up. The temperature of the
combustion chambers is reduced along with a more even temperature distribution. The temperature of the bores is increased.

F r
om the pump, coolant flows into each bank of the cylinder bl
ock. In each bank, approximately 50% of the coolant cools the
cylinder bores and the remainder is diverted th rough the bypass gallery to the cylinder head.
With the thermostat closed, coolant returns directly to the pump through the bypass on the thermostat housing.
With the thermostat open, coolant returns to the pump via the radiator.
The cooling system uses a mixture of water and Jaguar Anti-Freeze/Inhibitor (Dow 542).
The cooling system on a supercharged engine is similar, but has additional components for cooling the intake air.
Engine Cooling Co mponents - Supercharged Vehicles
ItemDescrip
tion
1Thr
ottle B
ody
2Hea
ter Return
3Coolant Pum p
4Ther
mostat Housing
5Vehicle Radia
t
or
6Hea
ter Su
pply
7Bleed
Outl
et (to expansion tank)
8EGR V
a
lve (when fitted)
9Bleed
Outl
et (to expansion tank)

A coola
nt outlet plastic pipe connects to the outlet port of ea
ch cylinder head to provide a common connection point for the
radiator top hose. It also incorporates the Engine Coolant Te mperature (ECT) sensor which provides a signal representing
coolant temperature at the cylinder heads. The outlet pipe has connections to supply the heater matrix and the bypass flow
to the thermostat housing. An in-groove ga sket, seals each of the outlet-to-cylinder head joints. An aluminium gasket seals
the ECT sensor to duct joint.
Coolant Outlet Duct - Supercharged

The coolant outlet duct on the supercharged engine performs exactly the same function as on the normally aspirated engine
and connects to the same ports on the engine. The main physical difference is that the thermostat housing has been
ItemDe
scription
1Bottom

Hose Connection
2The

rmostat Cover
3The

rmostat
4Coolan

t Outlet Duct
5B

reather Connection
6ECT Se

nsor
7Top Hose Conn

ection
8Bypa

ss to Water Pump
9Hea

ter Hose Connection

Whe r
e considered necessary, some hose conn
ections have an indication mark to ensure correct orientation of the hose when
being fitted.
All joints use spring-band clips, except small pipes on the bleed system joints - which use cobra clips. The heater feed and
return hoses use quick-connection unions.
Supply and return hoses for the heater are located between the cylinder banks.
A connection on the rear of the A-bank provides coolant supply for the electronic throttle and the EGR valve (where fitted).
The outlet from the electronic throttle connects to the return hose from the heater.
Cool
ant Header and Recovery Tanks
A recovery system comp
rising the header tank
and a recovery tank is fitted. The recove ry tank is located in front of the left
hand front wheel arch liner.
The header tank provides the cooling system filling point and carries the coolant level sensor. The pressure cap allows
controlled release of coolant to the re covery tank during normal operation.
The recovery tank accommodates the expansion of the system coolant during normal operation. On engine cool-down, the
coolant contracts and is returned to the main system.
Coo lin
g Fans
The two
rad
iator cooling fans are mounted in
a cowl assembly within the cooling module.
The fans are controlled by the ECM dependent on the demand fr om the cooling system (temperature) or the air conditioning
ItemDescrip
tion
1EGR
E
ngines
2Non
-
EGR Engines
3Hea
ter Connections

s
ystem (pressure).
Outputs from the ECM control the radiator fans control module, located behind the left hand side of the bumper, to operate
the fans in the series mode (slow), paralle l mode (Fast) or Off modes. Hysteresis in the temperature and pressure switching
values prevents 'hun ting' between modes.
Under hot operating conditions, the fans may continue to operat e for some time after the engine has been switched off, but
will stop automatically when the coolant te mperature has been sufficiently reduced.
Engine Coolant Temperature Sensor (ECT) and ECM

The engine coolant temperature (ECT) sensor is located in the coolant outlet pipe and reacts to engine coolant temperature
changes, providing an input to the Engine Control Module (ECM). The sensor has a negative te mperature coefficient so that
the sensor resistance decrea ses as temperature rises.
Temperature / Resistance Relationship Graph

T
emperature / Resistance
Relationship Table

Engi
ne Coolant Temperature Sensor (ECT) - Circuit Diagram

Intercooler Pump Relay - Circuit Diagram
T emper
ature (°C)
No
mi
nal Resistance (kOHM)
-2
015 .0
4
05.7
4
202.45
401.15
600.
584
800.3
2
1000.
184
ItemPar
t
Number
De
scrip
tion
1—Eng
i
ne Coolant Temperature (ECT) Sensor
2—Eng
i
ne to EMS Harness Connector
3—EMS Con
trol Modu
le

Engine Cooling - Engine Cooling
Diagn
osis and Testing
Related Faults / Codes

Adaptive
Fue
ling
Sym
p
tom Chart
Sy
m
ptom Chart
S
p
ecial Tool(s)

D
i
gital multimeter

Generi
c scan tool
Conditi
on
Possib
l
e Source
Acti
o
n
D
T
C P0171 System too lean bank
1 (A)
D T
C P0174 System too lean bank
2 (B)
Fuel delivery blockage Fu
el delivery pressure (low)
F
a
ulty injector (blocked)
Ai
r i
ntake system leak
F
u
el injector electrical fault
ECT sensor
faul
t
MAFM sensor fault IAT se
nsor fault

Thro
tt
le position sensor
fault
Mec hanica
l check
Mec
hanica
l check
Mec
hanica
l check
Mec
hanica
l check
Go t
o DTC P020
1 to 0208
Go t
o
DTC P0116 to 0118, P0125
Go t
o
DTC P0101 to 0103, P1104
Go t
o DTC P011
1 to 0113
Go t
o
DTC P0121 to 0123, P0222,
P0223
D T
C P0172 System too rich bank
1 (A)
D T
C P0175 System too rich bank
2 (B)
F u
el delivery pressure
(high)
F a
ulty injector (leaking)
F
u
el injector continuously
open
Ai r i
ntake system restricted

Fu
el injector electrical fault
ECT sensor
faul
t
MAFM sensor fault IAT sensor fault


Thrott

le position sensor
fault
Mec hanica
l check
Mec
hanica
l check
Mec
hanica
l check
Mec
hanica
l check
Go t
o DTC P020
1 to P0208
Go t
o
DTC P0116 to P0118, P0125
Go t
o
DTC P0101 to P0103, P1104
Go t
o DTC P011
1 to P0113
Go t
o
DTC P0121 to P0123, P0222,
P0223
Sy m
ptom
Possib
l
e Sources
Acti
o
n
D
T
C P0116 ECT circuit range / performance problem
Thermostat
Coo
l
ant level / contamination
Sensor out of range
Harness open circuit
Connector loose or corroded
*
*
*
*
*
GO to Pinpoint

Test A

*
D
T
C P0125 Insufficient coolant temperature for closed
loop fuel control
Thermostat
Coo l
ant level / contamination
Sensor out of range
Harness open circuit
Connector loose or corroded
*
*
*
*
*
GO to Pinpoint

Test A

*
D
T
C P0117 ECT circuit low input
Sensor o
p
en circuit
Harness open circuit
Harness short
*
*
*
GO to Pinpoint

Test B

*

Pinpoint test
A: P0116, P0125
Connector
loose or corroded
*
D
TC P0118 ECT circuit high input
Sensor short
Harness open circui

t
Harness short
Connector loose or corroded
*
*
*
*
GO to Pinpoint

Test C
*
D
TC P1474 Intercooler coolant pump relay malfunction
Intercooler pump relay
failure
Intercooler pump relay to ECM drive circuit
fault Intercooler pump relay coil ground circuit
fault Harness fault
Connector loose or corroded
Connector pins(s) bent or tracking between
connections ECM power supply fault
*
*
*
*
*
*
*
GO to Pinpoint

Test D
*
P
INPOINT TEST A : P0116, P0125
T
EST CONDITIONS
D
ETAILS/RESULTS/ACTIONS
A1

: RETRIEVE DTCS
•

NOTE: Battery and or ECM disconnection prior to scanning wi
ll erase all data, ensure that the correct DTC is present.
Conne
ct the scan tool
1
Have the DTC(s) and fr

eeze
frame data been recorded?
Yes GO to A2
A2: ENGINE
COOLANT SYSTEM CHECK
•

NOTE: Do not use the instrument display, if th
e ECT has failed this will not operate correctly.
Chec
k engine temperature rise using a thermocouple or
similar device.
1
Engine
temperature increasing?
Yes GO to A3
No Check coolant level
Check coolant for contamination
Check/test thermostat

All vehicles


21.
N
OTE: Install a new sealing washer.
• NOTE: Clean off any spillages.
Install the supercharger coolant fill plug.
Tighte
n to 45 Nm.
22. Remove the coolant expans ion tank pressure cap.
23. Switch ignition on.
24. CAUTION: Do not allow the supercharger water pump to
run dry. Failure to follow this instruction may result in damage to
the vehicle.
• NOTE: Leave the ignition switched on (do not start the engine)
for at least 2 minutes to allow the air charge cooler electric water
pump to operate and to purge an y air from the air charge cooler
radiator to the header tank.
Allow the supercharger pump to run and top up the system
through the coolant expansion tank.
25 . Swit
ch the ignition off.
26. Install the coolant expansion tank pressure cap.
27. START and RUN the engine.
28. CAUTION: Observe the engine temperature gauge. If
the engine starts to over-heat switch off immediately and allow to
cool. Failure to follow this inst ruction may cause damage to the
vehicle.
Run the engine at between 1500 and 2000 rpm until the cooling
fan operates.
29 .
Swi
tch off the engine.
30. Allow the engine to cool.
31. Check and top-up the coolant if required.

Engine Cooling - Coolant Outlet Pipe

Re
moval and Installation
Remov

al
Installation

1.
O
pen the engine compartment and fit paintwork protection
sheets.
2. Drain the radiator. Refer to Ge neral Procedures. Retain the
coolant drain tray in position to catch any spillage when
removing the outlet pipe.

3. Di
sconnect the hoses and multi-plug from the coolant outlet
pipe.
1. Release and reposition th e hose clip, and disconnect
the top hose.
2. Release and reposition th e hose clip, and disconnect
the heater hose.
3. Disconnect the multi-plug from the temperature sensor and unscrew the sens or from the outlet pipe.
4. Release and reposition the hose clip along the bypass
hose.

4. R
emove the coolant outlet pipe.
1. Remove the four bolts which secure the outlet pipe.
2. Remove the outlet pipe from the bypass hose and
from the cylinder heads.
5. Remove and discard the sealing rings from the outlet pipe
grooves.
1. Installation is the reverse of the remova l procedure. Use new
sealing rings on the coolant outlet pipe.
2. Tighten the coolant outlet pipe bolts to 10-14 Nm If replacing
the coolant temperature sensor, tighten to 15-19 Nm.
3. Refill the cooling system as de scribed in General Procedures.

Engine Cooling - Coolant Outlet Pipe
Remo
val and Installation
Remov
a
l
1.
Op
en the engine compartment and fit paintwork protection
sheets.
2. Drain the radiator. Refer to Ge neral Procedures. Retain the
coolant drain tray in position to catch any spillage when
removing the outlet pipe.

3. Disc onne
ct the top hose and br
eather pipe from the coolant
outlet pipe.
1. Release and reposition th e hose clip, and disconnect
the top hose.
2. Release and disconnect the breather pipe quick fit connector.
3. Disconnect the multi-plug from the temperature sensor and unscrew the sens or from the outlet pipe.
4. Release and reposition the hose clip along the bypass
hose.

4. Disc
onnect the bottom hose
from the thermostat housing.
1. Release and reposition th e hose clip along the hose.
2. Disconnect the bottom hose.

5. Disc
onnect the coolant outlet pipe from the cylinder heads.
1. Remove the four bolts which secure the outlet pipe.
2. Remove the outlet pipe from the bypass hose and
from the cylinder heads (still connected to the
heater hose).
6. Release and reposition the clip which secures the heater hose
to the outlet pipe and disconnect the hose. Remove the outlet
pipe.
7. Remove the thermostat from the outlet pipe.
1. Remove the three bolts which secure the thermostat cover to the outlet pipe.
2. Remove the thermostat cover, the thermostat and
the seal from the outlet pipe. Discard the seal.