1998 JAGUAR X308 Heater hose

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

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.

KS fail
ure
P0335Cranksh
a
ft positi
on (CKP) sensor
circuit malfunction
CK P
sensor disconnected
CKP sensor air gap
i
n
correct/foreign matter on face
CKP sensor sen
s
ing circuit open
circuit, short circuit to ground,
short circuit to high voltage
CKP s e
nsor failure
F
or CKP sensor circ ui
t tests,GO to
Pinpoint Test N.
.
P0340Camshaft position
(CMP) sensor
circuit malfunction
CM P
sensor disconnected
CMP sensor air gap
i
n
correct/foreign matter on face
CMP sensor sen
s
ing circuit open
circuit, short circuit to ground,
short circuit to high voltage
CMP s e
nsor failure
F
or CMP sensor circ ui
t tests,GO to
Pinpoint Test O.
.
P0351Igniti
on coil primary/secondary
circuit malfunction, cyl 1
ECM to ignit
ion module primary
circuit open circuit, short circuit to
ground, high resistance
Igniti
on module to ignition coil
primary circuit open circuit, short
circuit to ground, high resistance
Ignition modu le
ground circuit
open circuit, hi gh resistance
Ignition coil fail
ure
Ignition modul
e
failure
F
o
r ignition circuit tests,
REFER to Section 303
-07 En
gine
Ignition. P0352Ignit
i
on coil primary/secondary
circuit malfunction, cyl 3
P0353Ignit i
on coil primary/secondary
circuit malfunction, cyl 5
P0354Ignit i
on coil primary/secondary
circuit malfunction, cyl 7
P0355Ignit i
on coil primary/secondary
circuit malfunction, cyl 2
P0356Ignit i
on coil primary/secondary
circuit malfunction, cyl 4
P0357Ignit i
on coil primary/secondary
circuit malfunction, cyl 6
P0358Ignit i
on coil primary/secondary
circuit malfunction, cyl 8
P0400Exhaus t gas
recirculation (EGR)
flow malfunction
EGR valve c
onnector pins high
resistance
EGR pipe/exhaust manifol
d leak
EGR pipe blocke

d
EGR valve st

uck open/closed,
blocked
EGR valve fai
lure
For EGR
pinpoint t
ests,
REFER to Section 303
-08 En
gine
Emission Control.
P0405Exhaus
t gas
recirculation (EGR)
drive circuits open circuit
EGR valve power supply circuit
o p
en circuit
EGR valve t
o
ECM drive circuit pair
- EGR pins 1/3, 4/6 open circuit,
high resistance
EGR val v
e failure (stepper motor
open circuit)
For EGR pinpoint t
ests,
REFER to Section 303
-08 En
gine
Emissi
on Control.
P0406Exhaus t gas
recirculation (EGR)
drive circuits short circuit
EGR valve t o
ECM drive circuit pair
- EGR pins 1/3, 4/6 short circuit to
ground or high voltage
EGR val v
e failure (stepper motor
short circuit)
For EGR pinpoint t
ests,
REFER to Section 303
-08 En
gine
Emissi
on Control.
P0420Right-
hand catalytic converter
efficiency below threshold
HO2S di
sconnected.
HO2
S
to ECM wiring fault.
HO2
S
heater to ECM wiring fault.
HO2
S
heater failure.
HO2
S
failure.
Cat
a
lyst monitor sensor failure.
Catal
y
tic converter failure.
R
e
fer to pinpoint tests for components

listed. Visually inspect catalytic
converters.
P0442Evaporati v
e emissions system
(EVAP) leak detected
Fue l
filler cap missing
Fu

el filler cap seal faulty
EVAP system
leak (can
ister
damage, pipework damage)
EVAP v a
lve to ECM drive circuit
open circuit, short circuit, high
resistance
EVAP valve to engine pu rge pipe
damaged/blocked/leaking
EVAP ope r
ating vacuum hose
F
or evaporati
ve emissions pinpoint
tests,
REFER to Section 303
-1 3
Evaporative

Emissi
ons
.

Air Distribution and Filtering - Air Distri
bution and Filtering
Description an
d Operation
Air Distribution


Ou
tside air enters the plen
um via four inlets in the lower windshield panel.
If the air conditioning system is operating in FRESH mode (not recirculation mode), then air is drawn through the four
plenum apertures (and particle filters where fitted) and into the air conditioni ng unit via the blower interconnecting ducts in
the LH and RH blower assemblies. Air is c ooled and dehumidified as it passes through the evaporator and is then 'reheated'
to the required temperature as it passes through the heater matrix.
In RECIRCULATION mode, the air in the pass enger compartment is drawn into the air conditioning unit via the recirculation
air inlets on the blower assemblies.
In FRESH mode, air flows from the cabin into the trunk through a gap between the backlight and the parcel shelf. The air is
exhausted from the vehicle through extraction vent assemblies (incorporating one way flaps) whose outlets are above the
rear mufflers.
Air Flow Path

Air Distribution Modes
Bi
-level mode

Parts List
The heater circuit 'scavenges' coolant from the engine cooling system by mean s of an electric water pump. The water pump
has a protection circuit to inhibit operation when the coolant temperature is <16°C; this is to prevent possible damage to
the impeller due to the presence of coolant borne ice particles. Coolant is drawn from the en gine system through the water
valve inlet port into the heater matrix. The coolant passes thro ugh the bottom section of the heater matrix from left to right
filling the end tank of the matrix before returning through the top half of the ma trix and through the outlet ports of the
water valve and back into the engine cooling system.
Non return valves are located in the heat er bypass hose and the hose between the water pump and valve. These valves are
required to prevent coolant flowing in th e wrong direction at low engine speeds and restrict convected flow through the
heater after the engine is switched off.
When the exterior ambient temperature is > 0°C the refrigerat ion system automatically operates cooling and dehumidifying
incoming air before it is re -heated by the heater matrix.
Water Valve Assembly
Location
The water valve assembly is located above the water pump, in the engine compartmen t and is secured to the firewall by a
bracket. The valve operates by means of an electrical solenoid which oscillates the valve stem between the inlet and outlet
ports.
When in automatic mode, the water valve duty cycle is influenced by the following inputs to the A/CCM:
Outlet air temperature 'Air off' heater matrix temperature External ambient Coolant temperature
ItemPart NumberDescription
1—Assembly pump - water
2—Hose - from header tank
3—Hose / connector - return to engine
4—Hose - heater feed to matrix
5—Valve - non return (by-pass)
6—Hose / connector - feed from engine
7—Hose - heater return from matrix
8—Assembly valve - water
9—Valve - non return

Engine speed (valve closed with the engine not running) Demand (set) temperature In-car temperature sensor Solar sensor
Re-heating of the refrigerated air is contro lled by the time that the water valve is open (i.e. not energised) over a six secon d
interval. The duty cycle of the water valve, the time open / time closed, is controlled by the A/CCM.
Maximum heating demand will cause the water valve to be fu lly open (not energised) to allow maximum coolant flow
through the heater matrix.
At Maximum cooling, the water va lve will be fully closed (energised) to prevent hot (engine temperature) coolant entering
the heater circuit; the pump however will continue to circulate coolant through both the heater matrix and water valve
bypass.
The water valve defaults open when the ignition is OFF.
Under engine stall conditions, when ignition is ON, the water valve will be open.
Water Pump Assembly
Located in the same area as the water valve, the water pump continually circulates coolant through the heater matrix
except when the conditions below apply:
The engine coolant is below 16°C. The ignition is OFF. Under engine stall conditions, when ignition is ON. Control panel OFF
Non return valves
The heater bypass hose has a non-return valve, located between the engine feed and return hoses. The valve prevents the
water pump from recirculating coolant fro m the heater at low engine speeds.
The flow indicator arrow embossed on the valve bo dy MUST point towards the coolant header tank.
CAUTION: Coolant flow will be compromi sed if either valve is fitted incorrectly. Observe the correct direction.
A second non-return valve is located betw een the water pump and water valve. This valve prevents hot coolant from flowing
into the heater with the engine switched off. The flow indicator arrow MUST point towards the water pump.
Heater feed and return hoses
The heater feed and return hoses are connected to the engine feed and return hoses by 'Quick-Fit' connection unions. The
feed hose has a Norma R20 connector and the return hose a Norma push and seal connector. The coolant system bleed
joints have Cobra clamps. All remaining hose connections have spring band hose clamps.
The engine feed hose is connected to the engine bypass hous ing and the engine return hose is connected to the engine
water pump.
Clamp Identification

Heating and Ventilation - Heater Core and Evaporator Core Housing
Removal and Installation
Removal
1. Disconnect battery ground cable (IMPORTANT, see SRO
86.15.19 for further information).
2. Recover refrigerant from air co nditioning system; refer to
82.30.30.
3. Drain radiator coolant only; refer to 26.10.01 or (SC)
26.10.01.
4. Remove instrument panel for access, refer to 76.46.01.

5. From under the hood: Disconnect air conditioning pipes at the
evaporator.
1. Remove bolts.
2. Discard O-rings.
3. Install suitable blanking plugs.

6. Disconnect heater hoses from heater matrix pipes.
1. Release spring band clips and disconnect heater hoses.
2. Install suitable blanking plugs.

7. From inside the vehicle: re move driver footwell duct.
Remove screw.
Remove duct.
8. Remove upper steering column lower fixings.
1. Remove nut.
2. Remove bolt.