1999 JAGUAR S TYPE lock

V6 Engine
6
Basic Engine
Engine Structure
Basic engine construction is similar to the V8 in
that a structural bedplate is used which bolts to
the cylinder block to provide a very strong
housing for the crankshaft, minimising vibration.
Both units are of cast aluminium alloy and are
accurately aligned together by the use of eight
hollow dowels.
The cylinder block is fitted with dry cast iron
liners.
The oil sump is an aluminium alloy casting which
combines a sump body and oil pan in a single
structural component. The sump mounts to the
bedplate via an aluminium gasket incorporating a
silicone rubber seal.
D.303.1360
D.303.1360
ENGINE STRUCTURE
D.303.1364
ENGINE DATA LOCATIONS
Engine Identification Data
An engine identification code tag is located on the
bank 2 side of the front cover assembly.
Mains bearing selection codes are located at the
rear of the cylinder block and on the rear face of
the crankshaft flange. The two codes are
compared using reference data provided in the
JTIS service information to identify the correct
bearing.
Engine identification codeMains bearing selection codes
D.303.1364
AJ-V6/AJ28

V6 Engine
8
Cylinder Head
The aluminium alloy cylinder heads have square
squish combustion chambers with four valve
ports and a central spark plug. Each head is
aligned to the cylinder block via two split hollow
dowels and sealed with a composite stainless steel
gasket. Steel balls (10.11mm diameter) are used
to plug the external bores of the oilway drillings
and cup plugs are fitted to the water jacket
openings. Two half round aluminium cap inserts
are fitted via a sealant at the rear of the head.
Cam Cover
The cylinder heads are fitted with lightweight
polyester cam covers, (bank 2 is silver colored)
with silicone seals, to save weight and reduce
airborne noise. A central aperture allows access to
the coil on plug units and a second hole has a
grommet through which the VVT oil control valve
protrudes. The oil filler hole is in the LH cover.
D.303.1368
CYLINDER HEAD
D.303.1207
CAM COVER
D.303.1207
Cylinder Head Assembly
D.303.1368
AJ-V6/AJ28

V6 Engine
10
D.303.1204
CAMSHAFT DRIVE
D.303.1204
AJ-V6/AJ28
Camshaft Drive
Two timing chains are used, one for each cylinder
bank and driven by separate sprockets keyed to
the crankshaft. The chains are of the silent-type,
with a multiple link construction and sprocket
engagement on one side only.
Each chain has a hydraulic tensioner, fed from the
engine oil supply, which acts on a pivoted
tensioner arm with side flanges. Fixed guides bear
on the drive side of the chains and are unique to
each side.
A single piece aluminium alloy front cover is
aligned to the cylinder block by two dowels andencloses the timing gear. The crankshaft front oil
seal fits into the front cover and the inner lip
bears on the crankshaft damper.
Crankshaft timing disc
VVT unit

V6 EngineAJ-V6/AJ28
13
Oil Distribution
(see illustration on page 14)
Oil distribution within the block and cylinder
heads is similar to that of the V8 engine, the main
differences being in the filter and cooler
arrangement and the method of supplying the
VVT system.
Oil is drawn from the sump through the strainer
by the crankshaft driven pump, passes through
the externally mounted filter and oil cooler and
returns to the block. Distribution is via the main
gallery and crankshaft oilways to the lower
crankcase components and via branch feeds to
the chain tensioners and then cylinder head
components. Extra oilways in the cylinder heads
provide a built-in feed for the VVT components
(see VVT section).
Oil Pump
The oil pump is of the inner/outer rotor type with
the directly driven inner rotor located via flats on
the crankshaft and the body of the pump bolted
to the cylinder block. The oil pressure relief valveis located in the lower LH side of the pump. An
oil pick-up tube and strainer is bolted to the
pump inlet and projects directly down to the
sump. Oil foaming is reduced by the windage tray
bolted to the underside of the bedplate.
D.303.1211
Lubrication System
OIL PUMP
D.303.1211

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
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