1999 JAGUAR S TYPE cooling

ContentsAJ-V6/AJ28
1 G Gl
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Abbreviations 2
I In
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V V6
6
E
En
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gi
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Introduction 4
Engine Specifications 5
Basic Engine 6
Cylinder Head Assembly 8
Exhaust Manifold 12
Engine Mountings 12
Lubrication System 13
Crankcase Ventilation 15
Exhaust Gas Re-circulation (EGR) 17
Variable Valve Timing (VVT) 19
Air Induction System 21
Throttle Control System 25
Fuel System 29
Ignition System 30
Engine Cooling 31
Front End Accessories Drive 37
Engine Management Sensors 40
V V8
8
E
En
ng
gi
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e
Introduction 45
Basic Engine 46
Cooling System 49
Air Induction System 51
Variable Valve Timing (VVT) 53
Engine Management Sensors 54
Ignition System 54
Fuel Injection 56
Front End Accessories Drive 59
A Au
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Introduction 61
Specification 61
Construction and Operation 63
M Ma
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Introduction 64
Specification 64
Gear Selector Control 65
Flywheel and Clutch 65
Clutch Pedal Assembly 68
P Po
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M
Ma
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Introduction 69
Powertrain Control Module (PCM) 69
Subject Page

4
Introduction
D.303.1201
AJ-V6 ENGINEThe AJ-V6 is a water cooled six cylinder engine
configured as two banks of cylinders in a 60û V
formation. Valve operation is via chain driven
double overhead camshafts on each cylinder
bank. The engine is naturally aspirated but with a
unique air intake system which significantly
improves power output. Lightweight materials are
used extensively but the structural design is such
as to maintain a strong rigid assembly.The main features of the power unit are:
¥ three stage variable geometry intake manifold
¥ electronic throttle with cable-less operation
¥ two position variable valve timing
¥ returnless fuel system
¥ fail safe cooling system
V6 Engine
D.303.1202D.303.1201 &1202
AJ-V6/AJ28

V6 EngineAJ-V6/AJ28
15
Oil Cooler and Filter Mounting
The oil filter and oil cooler are mounted slightly
away from the cylinder block on an aluminium
alloy adaptor which is an integral extension of the
LH engine mount. The oil filter is a replaceable
canister screw on type and the cooler is fixed by a
single through bolt to the adaptor. Both
components are connected to the cylinder block
through internal oilways in the adaptor casting
and via an interfacing filter mounting in the
block. A hollow bolt passes through the
adaptor/engine mount and screws into the centre
channel of the block filter mounting to provide
the oil return from the cooler to the cylinder
block.
The adaptor mounted oil cooler is an oil to water
heat exchanger and the coolant matrix is
connected via hoses into the main coolant system
at the radiator bottom hose (see Cooling System).
ENGINE OIL PRESSURE AND OIL TEMPERATURE SENSORS
D.303.1205
OIL COOLER AND FILTER ASSEMBLY
EOP Sensor
EOT Sensor
D.303.1205
D.303.1371
Engine Oil Pressure (EOP) and Oil
Temperature (EOT) Sensors
EOP and EOT sensors are fitted on the LH side of
the cylinder block in the return feed from the oil
cooler. The oil temperature is monitored to
provide data for the VVT system.
Oil Cooler
Hollow Bolt
Engine Mount/
Oil Cooler Adapter

V6 Engine AJ-V6/AJ28
16
Crankcase Ventilation
Full Load Ventilation
Breather outlets on each cam cover are connected
via hoses and a Tee junction to the intake duct to
provide full load crankcase ventilation.
Positive Crankcase Ventilation
Under closed or near closed throttle conditions,
engine breathing is mainly via the positive
crankcase ventilation (PCV) system. An oil
separator is bolted to the top of the engine block
between the cylinder banks and has an outlet
connected to the intake manifold via an in-line
PCV valve and hoses. The PCV valve has a spring
J.303.1286
FULL LOAD VENTILATION
D.303.1286
loaded plunger which opens under the intake
vacuum created at low throttle openings. When
the PCV valve is open, crankcase gases are drawn
through the separator, depositing oil droplets on
an internal baffle for return to the sump.
The PCV inlet tube to the manifold is heated by
the engine cooling system.
J.303.1290
POSITIVE CRANKCASE VENTILATION
D.303.1290
Oil Separator
PCV valve

V6 Engine AJ-V6/AJ28
26
J.303.1316
J.303.1362
THROTTLE BODY ASSEMBLY
TP/APP SENSORS - GENERAL CHARACTERISTICStwo fixed external connectors. The TAC module is
mounted on the underside of the throttle body
and drive motor unit with its upper connector
plugged directly into a fixed recessed connector
on the drive motor. The front connector provides
the main control interface with the PCM. Note
that the motor unit and the TAC module are
electronically calibrated together on initial
manufacture (the TAC module ÔlearnsÕ the motor
characteristics) and must not be individually
replaced. The throttle assembly as a whole is not
a serviceable item except for the TP sensor.
Two stub pipes at the rear of the throttle body are
connected via hoses into the engine cooling
system to provide throttle de-icing.
Throttle Position (TP) Sensor
The TP sensor is bolted to the non drive end of
the throttle body and is rotated directly (1:1) by
the blade ended throttle shaft. It has three non-
contacting, Hall effect, sensing elements which
are supplied from the PCM by two separate 5V
reference and signal return lines. Each sensor
provides an independent analogue output to the
PCM. For additional security, each sensor element
has a unique rotational angle to output voltage
characteristic (see Figure); the three outputs are
compared by the PCM for the expected values for
a particular throttle angle. This arrangement
identifies a sensor or wiring fault including a short
circuit between outputs.
Output Voltage
Sensor Rotor AngleDegrees
V
TAC Module
J.303.1382 J.303.1316
TP Sensor
Drive Motor
Sensor 3 Sensor 2Sensor 1
Throttle Body

V6 EngineAJ-V6/AJ28
31
J.303.1365
Engine Cooling
Cooling System
Engine cooling is via a conventional re-circulation
system between the engine assembly and front
mounted coolant to air radiator. Coolant flow is
from the front of the engine, dividing to pass
around each bank of cylinders towards the rear
and then flowing forward through the cylinder
heads. The coolant from the engine returns to the
top RH side of the radiator, by-pass circuit and
also provides the hot input feed to the cabin
V6 ENGINE COOLING SYSTEMheater system. The bottom hose feeds coolant
from the radiator via the thermostat to the
coolant pump and also provides the cooling
circuit for the oil. A differential pressure orifice in
the bottom hose causes a flow through the engine
mounted oil cooler.
A coolant reservoir system (or de-gas system) is
used which is similar to previous (pre 1998MY)
vehicles.
The reservoir bottle is mounted at the rear left
1. Radiator
2. Top hose
3. Bottom hose
4. Thermostat
5. Coolant Pump
6. Engine oil cooler7. Reservoir bottle
8. Electronic throttle
9. V6 engine
10. Heater control valve
11. Heater unit
12. Bleed valve
1
10
5
11
9
4
6
2
3
8
12
7
J.303.1365

V6 Engine AJ-V6/AJ28
34Coolant Pump
The coolant pump is fitted via three bolts to the
engine front cover. The pulley is mounted in-
board of the pump assembly, between the pump
and front cover, and has a smooth surface which
is driven from the outer, non ribbed side of the
drive belt.
Coolant returns from the radiator and cabin
heater system are connected via hoses to inlets on
the front of the pump assembly. The outlet from
the pump is connected to the engine block via a
hose and a tubular casting bolted to the top front
of the block between the cylinders.
Radiator and Cooling Fan Assembly
The engine radiator is one component of the
cooling pack assembly which also includes the
PAS and transmission heat exchangers and the
A/C condenser. The cooling pack assembly and
the PAS and A/C systems are described in the
ÔS-TYPE IntroductionÕ Technical Guide and
transmission cooling is described elsewhere in
this Guide.
The radiator consists of an aluminium core,
26mm in thickness, with crimped on plastic end
tanks. A single electrical cooling fan and a fan
D.303.1213
COOLANT PUMP
D.303.1213
D.303.1375
RADIATOR AND FAN SHROUD ASSEMBLY
D.303.1375
Fan Speed
Regulator Module

V6 EngineAJ-V6/AJ28
35
J.303.1384
ENGINE BLOCK HEATER
D.303.1384
J.303.1377
FAN SPEED REGULATOR MODULE COOLING DUCT speed regulator module are fixed to the glass
filled nylon fan shroud assembly which is
mounted on the rear of the radiator end tanks via
two lower slots and pegs, two upper screws and
two clips at the bottom of the radiator. The A/C
system receiver drier bottle is also mounted on
the fan shroud assembly - see the
ÔS-TYPE IntroductionÕ Technical Guide.
The 500W fan motor drives a glass filled nylon
impeller over a continuously variable speed range
from 300RPM to 2900RPM and is controlled by a
regulator module mounted at the lower LH side of
the fan shroud. Since the fan speed regulator
module provides power drive to the fan, it has a
finned heat sink outer casing and is enclosed
within a cooling duct. The ducting extends
forwards below the cooling pack to receive an
inflow of air.
The radiator drain is located on the RH end tank.
Coolant
A new type of anti-freeze fluid is used for the
coolant mixture. This product is a conventional
ethylene glycol based fluid but with new organic
corrosion inhibitors instead of the silicate, nitrite
and other additives which are normally used.
These new corrosion inhibitors do not form a
deposit on the inner surfaces of the coolant
system and therefore provide improved heat
transfer (more efficient cooling), better
component protection and an extended coolant
life due to the low rate of depletion of the
additives. The recommended coolant change is
every five years or 250,000km (150,000miles).
Engine Block Heater
For markets subject to very low temperatures, an
engine coolant heater, for connection to an
external mains electrical supply, is screwed into
the RH side of the cylinder block adjacent to the
knock sensor. Two heaters are available, a 400W
115V unit with a two pin connector and a 600W
230V unit with flying lead.
J.303.1377