engine coolant JAGUAR X308 1998 2.G Workshop Manual

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

Compressor:
Features
Engine mounted, driven by the accessory drive belt. Fixed displacement type. High-pressure relief valve, to avoid system over-pressure. ECM controlled clutch energized via a relay.
Receiver drier:
Vertically mounted on the ri ght-hand side of the engine compartment next to the engine coolant radiator. Fitted with the high-side charge port. Includes a fluorescent tracer dye me chanism to aid leak detection.
ItemPart NumberDescription
1—Compressor assembly
2—Condenser
3—Evaporator and heater matrix (internal)
4—Receiver drier
5—4-level pressure switch
6—Expansion valve (internal)
7—High-side charge port
8—Low-side charge port
9—Suction muffler
10—Discharge hose
11—Discharge pipe
12—Suction hose
13—Suction pipe
14—Liquid line
15—Jumper hose (condenser hose)

Air Conditioning - Condenser Core
Removal and Installation
Removal
1. Disconnect battery ground cable (IMPORTANT, see SRO
86.15.19 for further information).
2. Drain radiator coolant only; refer to 26.10.01 or (SC)
26.10.01.
3. Recover refrigerant from air co nditioning system; refer to
82.30.30.
4. Release both gas struts, set the engine cover fully forward to
the service access position an d support with a wooden (or
similar) strut.
5. CAUTION: Take care not to damage hood or radiator
grille.
Remove twin fan and motor as sembly; refer to 26.25.12.

6. Disconnect radiator bleed hose.
Release connection.
7. Remove retaining clip which secures transmission oil cooler
upper and lower pipes.

8. Disconnect transmission oil cooler lower pipe from radiator.
1. Release union nut and disconne ct pipe.
Discard O-ring seal.
2. Install suitable blanking plugs.
9. From above the vehicle, discon nect transmission oil cooler
upper pipe from radiator.
1. Release union nut and disconne ct pipe.
Discard O-ring seal.
2. Install suitable blanking plugs.

Control Components - Control Components
Description and Operation
System Controls
The climate control system is controlled by : 1. 1. Manual input from the operator, via the center console located control panel.
2. 2. Automatically by means of the A/CCM.
Output is based upon input from the following devices:
Motorized In-car aspirator External air temperature sensor Coolant temperature sensor Heater 'air-off' (the temperature of the air leaving the matrix fins) temperature sensor Evaporator 'air-off' (the temperature of the air leaving the evaporator fins) temperature sensor Solar sensor Left hand blower recirculation / fresh air flap potentiometer Right hand blower recirculation / fresh air flap potentiometer Upper air distribution box (ADB) center and side face flap servomotor potentiometer ADB defrost flap servomotor potentiometer Air conditioning unit Foot flap servomotor potentiometer Air conditioning unit Cool Air Bypass flap servomotor potentiometer Thumbwheel controls on the facia vent assemblies which provide manu al adjustment of the airflow volume. Road and engine speed signals input to the A/CCM
Climate Control Panel
Communication between the control panel and the A/CCM is via a serial data communications link.

Switching the Climate Control system ON
The climate control system can be switched ON by pressing one of the following :
Ref #1 On / Off (resumes the system on in the previous settings).
Ref #10 A / C (resumes the system on in the previous settings).
Ref #11 AUTO (resumes the system on at the previous temperature setting).

Ref #12 DEF (resumes the system on at the previous temperature setting).
Button (switch) logic
All buttons with an integral LED state lamp conform to the following operating logic.
When the state lamp is lit the relevant func tion is operational. From this condition, pressing the button will de-activate the
function, confirmed by the LED being de-energized and the pres ence of a single audible 'beep'. A single 'beep' will
accompany the state lamp to confirm function re-selection.
1. 1. ON / OFF and manual fan speed.
Pressing this knob activates the system ON at the last settin g or switches the system OFF. Rotate the knob clockwise to
increase and anti-clockwise to decrease fan speed and thus airflow.
With the system OFF, ram air is available by the selected air di stribution mode (indicated by state lamp). Air flow will NOT
occur unless a manual air distribution mo de is selected, this air being unconditioned and flow dependent upon vehicle
speed.
• NOTE: The blowers are inhibited until the engine coolant te mperature is > 35°C, unless DEFROST, FACE or DEMIST modes
are selected.
2. 2. Manual Air Recirculation
Closes the outside air intakes of the blower asse mblies and recirculates air within the vehicle.
Two options of control are available :
Timed Recirculation. Pressing the button for less than 1.5 seconds lights up the LED (confirmed by a single bleep).
This provides recirculation of interior air for a period of approximately 5 minutes. Pressing the button within five
minutes returns the system to fresh air intake mode.
Continuous Recirculation. Pressing and holding the button for more than 1.5 seconds lights up the LED (confirmed by two beeps). This provides continuous reci rculation of interior air. Pressing the button returns the system to fresh air
intake mode.
• NOTE: Avoid using manual air recirculatio n for prolonged periods in cold weather, this may result in interior misting of
glass.
3. 3. Temperature Scale Selection
Press the appropriate button to display temperatures in degrees Celsius or Fahrenheit.
4. 4. Manual Fan Speed
Rotating the fan speed control knob (to vary fan speed) will di splay a proportional number of horizontal bars on the LCD.
There are total of eleven manual fan speeds available.
5. 5. Temperature Display
Indicator of internal demand temperatur e or external ambient temperature. The external ambient is updated every 4
seconds when the road speed > 25 km / h.
6. 6. Scale
Selected temperature scale, Celsius or Fahrenheit.
7. 7. External temperature
Symbol indicates when this option is selected

Inputs / Outputs
1.1. Engine speed:
Input to the A/CCM from the ECM. Heated windshield and backli ght will be inhibited when engine speed < 50 RPM.
2. 2. Vehicle speed:
Input from the instru ment cluster. Blower speed control to minimise the effects of ram ai r. Road speed compensation is inhibited when maximum
cooling LO, or maximum heating HI, is selected; also inhi bited in defrost mode with airflow set to maximum.
Used to determine the frequency at which the exterior temperature display is updated.
3. 3. Coolant temperature (signal derived from ECM via instrument cluster):
Input from the heater matrix temperature sensor used to control water valve and thus vent temperatures. Used to monitor the temperature of coolant at the heater matrix to assist the control of air outlet temperature. Used to inhibit the blowers when heating is selected and the engine coolant temperature is below 30°C. Is used to provide progressive increase in blower speed up to 60°C. To inhibit the water valve and pump when the coolant temperature is = < 10°C
Sensors and Controls
Solar Sensor

other sensors. This feature prevents the effects of sudden changes in air outlet temperatures due to factors such as:
Recirculating air from the engine cooling pack at low vehicle speeds Sudden changes in ambient temperature The effects of water splash
Motorised In-car Aspirator.

An intake grille (mounted on the fascia , outboard of the steering column and below the EOD vent) houses the aspirator
thermister. The remotely mounted motor / fan assembly draws ca bin air through the grille and thus over the thermistor; a
flexible hose connects both components.
The electrical resistance of the thermistor changes in response to variations in air temperatur e, this change being converted
into an electrical signal. The A/CCM uses this signal to adjust the temperature, airflow and air distribution from the air
conditioning unit.
Coolant Temperature Signal.
This signal is supplied to the A/CCM from the instrument cluster, the input being required to:
Provide blower inhibit control , to avoid the system in heat ing mode delivering cold air when the coolant temperature is below 35°C unless DEFROST is selected. To progressively increase the fan speed up to maximum blower speed during warm up control. To assist in the control of the outlet temperature. To avoid possible pump or valve damage ca used by ice particles in the coolant.
Compressor ON Signal.
This signal monitors the compressor relay to confirm the compressor operating state and so provide relevant fault
information.
Servo Motor Control.
Flap position, which directs the flow of air through the system, is controlled by servo motors; these may be driven in either
a clockwise or anti-clockwise direction by signals from the A/ CCM. Motor, thus flap position, is monitored via a feedback
potentiometer which is situated within the motor housing.
Servo motors control the following flaps:

RH and LH Air Intake (Fresh / Recirc) Center Vent Defrost Foot Cool Air Bypass
Blower Motor Control.
The A/CCM controls the speed of two blower motors which deliver airflow to the air conditioning unit. The blower motors are
regulated by power transistor modules which pr ovide a linear variation of blower speed.
Filter Compensation
Where particle filters are fitted as 'after market' items the A/CCM program must be changed to allow higher AUTO blower
speeds; this compensates for the slight loss of air flow. Access to the program is by PDU.
Vehicles with filters fitted OEM will have this facility enabled by Jaguars Cars Ltd.
Relationship Manual Contro l Blower Speed / Voltage
• NOTE: Blower motors are inhibited when the engine coolant temperature is below 35°C and heating is demanded, unless
DEFROST / DEMIST is selected.


Blower ModeDisplay Output - No of BarsBlower Motor Voltage (V)
OFFNil0.0
Manual LO14.00
24.33
Manual M124.67
35.00
Manual M235.33
45.67
46.00
Manual M346.33
56.67
Manual M457.00
67.33
67.67
Manual M568.00
78.33
78.67
Manual M679.00
89.33
89.67
Manual M7810.00
910.33
Manual M8910.67
1011.00
Manual M91011.33
1111.67
Manual HI and DEFROST1112.00

System Self-test
Other conditions which may exist but will NOT log fault codes:
Associated Faults
System Self-test
Panel Communication Check
The panel communication check veri fies the inputs and outputs from the control panel to the A/CCM.
Actuator Check Procedure
The system self test procedure drives all the actuator moto rs, to check their operation. If an actuator is operating
incorrectly or operating outside of its limi ts then a fault code will be present.
Before commencing with the actuator check procedure, ensure the ca r is operating under normal conditions.
1. 1. Switch ignition OFF.
2. 2. Press and hold the RECIRC and AUTO buttons simult aneously, switch ignition ON and run the engine.
3. 3. All the control panel LEDs and all LCD segments will flas h on and off. Any function LED indicator which does not
flash on / off suggests a fault condition within that area of the panel or, with the LED.
Any LCD element which fails to flash on / off indicates a fault within the display element or panel.
4. 4. Press AUTO
43 Cool air by-pass
motor faultHarness / connector fault
Servo motor seized or sticking
Flap seized or sticking
*
*
*Refer to PDU
*
43 Cool Air by-pass
motor faultHarness / connector fault
Servo motor seized or sticking
Flap seized or sticking
*
*
*Refer to PDU
*
44 Defrost vent motor
faultHarness / connector fault
Servo motor seized or sticking
Flap seized or sticking
*
*
*Refer to PDU
*
45 Centre vent motor
faultHarness / connector fault
Servo motor seized or sticking
Flap seized or sticking
*
*
*Refer to PDU
*
46 Foot vent motor
faultHarness / connector fault
Servo motor seized or sticking
Flap seized or sticking
*
*
*Refer to PDU
*
SymptomPossible SourcesAction
No heatAirlock in system.
*Refer section 303-03 for fill / bleed procedure
*
Heater water pump inoperative
Coolant flow valve stuck closed
*
*Check operation and circuit
*
Faulty engine coolant thermostat
*Renew as required
*
One vent failing to open / closeBroken linkage.
*Renew as required
*
Poor airflowBlower motors - incorrect operation
*Check operation and circuit
*
ItemCheck LEDCondition
IgnitionDefrostIGN input at 12V, check LED is illuminated
AuxiliaryFaceAUX input at 12V, check LED is illuminated
ClockFeet / faceClock input normal, check LED is illuminated
Start inputFootStart input normal, check LED is illuminated
Data outScreen / footData out input normal, check LED is illuminated
Dimmer overrideRecirc.Dimmer override input ON, check LED is illuminated