1999 LAND ROVER DISCOVERY oil level

COOLING SYSTEM - V8
DESCRIPTION AND OPERATION 26-2-7
Inlet manifold - Cooling connections
Coolant leaves the cylinder block via an outlet pipe attached to the front of the air intake manifold. The pipe is
connected to the thermostat housing and the radiator by a branch hose off the radiator top hose.
Hot coolant from the engine is also directed from the inlet manifold via pipes and hoses into the heater matrix. Coolant
is circulated through the heater matrix at all times when the engine is running.
A further tapping from the inlet manifold supplies coolant to the throttle housing via a hose. The coolant circulates
through a plate attached to the bottom of the housing and is returned through a plastic bleed pipe to an expansion
tank. The hot coolant heats the air intake of the throttle housing preventing ice from forming.
An Engine Coolant Temperature (ECT) sensor is fitted in the inlet manifold adjacent to the manifold outlet pipe. The
sensor monitors coolant temperature emerging from the engine and sends signals to the ECM for engine
management and temperature gauge operation.

+ ENGINE MANAGEMENT SYSTEM - V8, DESCRIPTION AND OPERATION, Description - engine
management.
Expansion tank
The expansion tank is located in the engine compartment. The tank is made from moulded plastic and attached to
brackets on the right hand inner wing. A maximum coolant when cold level is moulded onto the tank.
Excess coolant created by heat expansion is returned to the expansion tank from the radiator bleed pipe at the top of
the radiator. An outlet pipe is connected into the pump feed hose and replaces the coolant displaced by heat
expansion into the system when the engine is cool.
The expansion tank is fitted with a sealed pressure cap. The cap contains a pressure relief valve which opens to allow
excessive pressure and coolant to vent through the overflow pipe. The relief valve opens at a pressure of 1.4 bar (20
lbf.in
2) and above.
Heater matrix
The heater matrix is fitted in the heater assembly inside the passenger compartment. Two pipes pass through the
bulkhead into the engine compartment and provide coolant flow to and from the matrix. The pipes from the bulkhead
are connected to the matrix, sealed with 'O' rings and clamped with circular rings.
The matrix is constructed from aluminium with two end tanks interconnected with tubes. Aluminium fins are located
between the tubes and conduct heat away from the hot coolant flowing through the tubes. Air from the heater
assembly is warmed as it passes through the matrix fins. The warm air is then distributed into the passenger
compartment as required.

+ HEATING AND VENTILATION, DESCRIPTION AND OPERATION, Description.When the engine is
running, coolant from the engine is constantly circulated through the heater matrix.
Radiator
The 45 row radiator is located at the front of the vehicle. The cross-flow type radiator is manufactured from aluminium
with moulded plastic end tanks interconnected with tubes. Aluminium fins are located between the tubes and conduct
heat from the hot coolant flowing through the tubes, reducing the cooling temperature as it flows through the radiator.
Air intake from the front of the vehicle when moving carries heat away from the fins. When the vehicle is stationary,
the viscous fan draws air through the radiator fins to prevent the engine from overheating.
Two connections at the top of the radiator provide for the attachment of the top hose and bleed pipe. A connection at
the bottom of the radiator allows for the attachment of the bottom hose to the thermostat housing.
Two smaller radiators are located in front of the cooling radiator. The lower radiator provides cooling of the gearbox
oil and the upper radiator provides cooling for the engine oil.

+ MANUAL GEARBOX - R380, DESCRIPTION AND OPERATION, Description.

+ AUTOMATIC GEARBOX - ZF4HP22 - 24, DESCRIPTION AND OPERATION, Description.

+ ENGINE - V8, DESCRIPTION AND OPERATION, Description.
Pipes and hoses
The coolant circuit comprises flexible hoses and metal formed pipes which direct coolant into and out of the engine,
radiator and heater matrix. Plastic pipes are used for the bleed and overflow pipes to the expansion tank.
A bleed screw is installed in the radiator top hose and is used to bleed air during system filling. A drain plug is fitted
to each cylinder bank in the cylinder block. These are used to drain the block of coolant.

COOLING SYSTEM - V8
DESCRIPTION AND OPERATION 26-2-9
Viscous fan
1Coolant pump pulley drive attachment
2Fan blades3Bi-metallic coil
4Body
The viscous fan provides a means of controlling the speed of the fan relative to the operating temperature of the
engine. The fan rotation draws air through the radiator, reducing engine coolant temperatures when the vehicle is
stationary or moving slowly.
The viscous fan is attached to the coolant pump drive pulley and secured to the pulley by a nut. The nut is positively
attached to a spindle which is supported on bearings in the fan body. The viscous drive comprises a circular drive
plate attached to the spindle and driven from the coolant pump pulley and the coupling body. The drive plate and the
body have interlocking annular grooves with a small clearance which provides the drive when silicone fluid enters the
fluid chamber. A bi-metallic coil is fitted externally on the forward face of the body. The coil is connected to and
operates a valve in the body. The valve operates on a valve plate with ports that connect the reservoir to the fluid
chamber. The valve plate also has return ports which, when the valve is closed, scoop fluid from the fluid chamber
and push it into the reservoir under centrifugal force.
Silicone fluid is retained in a reservoir at the front of the body. When the engine is off and the fan is stationary, the
silicone fluid level stabilises between the reservoir and the fluid chamber. This will result in the fan operating when the
engine is started, but the drive will be removed quickly after the fan starts rotating and the fan will 'freewheel'.
At low radiator temperatures, the fan operation is not required and the bi-metallic coil keeps the valve closed,
separating the silicone fluid from the drive plate. This allows the fan to 'freewheel' reducing the load on the engine,
improving fuel consumption and reducing noise generated by the rotation of the fan.
When the radiator temperature increases, the bi-metallic coil reacts and moves the valve, allowing the silicone fluid
to flow into the fluid chamber. The resistance to shear of the silicone fluid creates drag on the drive plate and provides
drive to the body and the fan blades.

COOLING SYSTEM - V8
DESCRIPTION AND OPERATION 26-2-11
Viscous fan operation
A = Cold, B = Hot
1Drive plate
2Fan body
3Clearance
4Valve plate
5Valve
6Bi-metallic coil7Fluid seals
8Ball race
9Fluid chamber
10Reservoir
11Return port
When the engine is off and the fan is not rotating, the silicone fluid stabilises within the fluid chamber and the reservoir.
The fluid levels equalise due to the return port in the valve plate being open between the fluid chamber and the
reservoir. In this condition, when the engine is started, silicone fluid is present in the fluid chamber and causes drag
to occur between the drive plate and the body. This causes the fan to operate initially when the engine is started.
As the fan speed increases, centrifugal force and a scoop formed on the fluid chamber side of the valve plate, pushes
the silicone fluid through the return port in the valve plate into the reservoir. As the fluid chamber empties, the drag
between the drive plate and body is reduced, causing the drive plate to slip. This reduces the rotational speed of the
fan and allows it to 'freewheel'.
When the coolant temperature is low, the heat emitted from the radiator does not affect the bi-metallic coil. The valve
remains closed, preventing fluid escaping from the reservoir into the fluid chamber. In this condition the fan will
'freewheel' at a slow speed.
As the coolant temperature increases, the heat emitted from the radiator causes the bi-metallic coil to tighten. This
movement of the coil moves the valve to which it is attached. The rotation of the valve exposes ports in the valve plate
which allow silicone fluid to spill into the fluid chamber. As the fluid flows into the clearance between the annular
grooves in the drive plate and body, drag is created between the two components. The drag is due to the viscosity
and shear qualities of the silicone fluid and cause the drive plate to rotate the body and fan blades.
As the coolant temperature decreases, the bi-metallic coil expands, rotating the valve and closing off the ports in the
valve plate. When the valve is closed, centrifugal force pushes silicone fluid through the return port, emptying the fluid
chamber. As the fluid chamber empties, the drag between the drive plate and the body is reduced and the body slips
on the drive plate, slowing the rotational speed of the fan.

MANUAL GEARBOX - R380
DESCRIPTION AND OPERATION 37-3
1Front cover
2Input shaft oil seal
3Oil filler/level plug
4Sealing washer
5Oil drain plug
6Gear case
7Interlock spool retainer, bolt and 'O' ring
8Centre plate
9Locating dowels
10Selector plug, detent balls and spring
11Splash shield and retaining bolt
12Extension housing
13Gate plate and retaining bolt
14Interlock spool retainer, retaining bolt and 'O'
ring – if fitted – extension housing
15Inhibitor cam spring
16Inhibitor cam
17Reverse inhibitor shaft
18Output shaft oil seal
19Oil seal collar
20Oil pump and retaining bolt
21'O' ring
22Reverse lamp switch23Oil by-pass block - UK and European models
24Bolt - oil by-pass block
25'O' ring - oil by-pass block
26Thermostat and housing - non UK and non
European models
27'O' ring - thermostat housing
28Bolt - thermostat housing
29Oil pick-up pipe
30Oil filter
31Oil pick-up ring
32Rubber gaiter
33Cable tie
34Upper gear lever
35Clamp bolt
36Bias springs
37Bolts and washers - bias adjusting plate and
housing
38Bias adjusting plate
39Lower gear lever and ball
40Railko bush
41Oil seal
42Gear change housing

MANUAL GEARBOX - R380
DESCRIPTION AND OPERATION 37-7
Description
General
The R380 all synchromesh gearbox has five forward speeds and reverse and is mounted in line with the engine. The
clutch bell housing is bolted to the front of the gearbox and the transfer box is mounted at the rear.
Gearbox casings
Gearbox casings consist of a front cover, gearcase, centre plate and extension housing. All casings with the exception
of the front cover are located to each other by dowels and sealed. Gearbox filler/level and drain plugs are located in
the gearcase.
Reverse lamp switch
A reverse lamp switch is inserted into the extension housing. Selection of reverse gear will close the switch allowing
current from fuse 25 to flow through the switch to illuminate the reverse lamps. The switch also provides a feed to the
BCU and the electrochromic automatic interior mirror - if fitted; the mirror moving from the dimmed position if
applicable.
Gearchange assembly
The gearchange assembly is bolted to the top of the gearcase, the upper gear lever being attached to the lower gear
lever by means of a clamp bolt. The lower gear lever ball is housed in a Railko bush inserted in the gear change
housing, the end of the lever locating in the selector yoke which is attached to the end of the selector shaft. Bias
springs provide a positive return of the gear lever to the neutral position with selection of 1st/2nd and 5th/reverse gears
being against bias spring pressure. Spring loaded detent balls fitted in the centre plate locate in grooves in the selector
shaft to provide positive gear and neutral selection.
Lubrication
Lubrication is by an oil pump located in the extension housing and driven by the layshaft with additional lubrication
being provided by splash. The pump directs oil via a filter and internal drillings in the output shaft to lubricate the
components. On non UK and non European models, provision for oil cooling is by means of a thermostat housed in
a cover bolted to the side of the extension housing. The cover incorporates tappings for connections to an oil cooler.
On UK and European models, the thermostat and cover are replaced by an oil by-pass block.
Internal pressures produced within the gearbox are vented to atmosphere via a plastic breather pipe. The pipe is
attached to the extension housing and is routed across the top of the gearcase and secured at the open end by a clip
attached to the engine cylinder block.
Selector shaft and forks
Selector forks for 1st/2nd, 3rd/4th and 5th/reverse gears are located on a single selector shaft; the 1st/2nd and 3rd/
4th selector forks are inside the main gearcase whilst the 5th/reverse selector fork is inside the extension housing.
Each of the selector forks locates inside its corresponding synchromesh hub.
Synchromesh assemblies
Each synchromesh assembly is located on the output shaft adjacent to its corresponding gears and comprises a
synchromesh ring, hub, slippers and sleeve. The hubs and slippers are retained in the sleeves by means of spring
clips. 1st/2nd and 3rd synchromesh assemblies are fitted with double synchromesh rings whilst 4th, 5th and reverse
assemblies are fitted with single rings.
The gear train
The gear train comprises an input shaft, output shaft, layshaft and reverse idler shaft together with their appropriate
gears and synchromesh assemblies.
The gear train input shaft, output shaft and layshaft are supported by taper roller bearings with all gears on the input
and output shafts running on caged needle roller bearings. Layshaft gears are integral with the shaft with the
exception of reverse/5th gears which are splined to the shaft and retained with a nut. 1st, 2nd, 3rd and 4th gears are
shot peened to improve durability. The reverse idler shaft and gear are supported in the centre plate by a caged
needle roller bearing. End-float of the output shaft and layshaft is controlled by selective shims located in the centre
plate whilst reverse idler shaft end-float is controlled by a selective shim located behind reverse gear.

MANUAL GEARBOX - R380
REPAIRS 37-23
Cooler - oil - gearbox - Diesel
$% 37.24.02
Remove
1.Remove intercooler.

+ ENGINE MANAGEMENT SYSTEM -
Td5, REPAIRS, Intercooler.
2.Position absorbent cloth under each gearbox
oil cooler hose connection to collect spillage.
3.Push against coupling release ring and
disconnect both fluid hoses from oil cooler.
CAUTION: Always fit plugs to open
connections to prevent contamination.
4.Remove screw securing oil cooler to radiator.
5.Release oil cooler from location on radiator,
and remove the oil cooler.
CAUTION: Always fit plugs to open
connections to prevent contamination.Refit
1.Fit oil cooler to radiator and secure with screw.
2.Ensure connections are clean and secure
hoses to cooler.
3.Fit intercooler.

+ ENGINE MANAGEMENT SYSTEM -
Td5, REPAIRS, Intercooler.
4.Top up gearbox oil level.

+ MAINTENANCE, PROCEDURES,
Manual gearbox.

TRANSFER BOX - LT230SE
41-4 DESCRIPTION AND OPERATION
Main casing components – Vehicles up
to 03 model year
1Retaining plate
2Stake nut - intermediate shaft
3Bolt - retaining plate
4'O' rings - intermediate shaft
5Bearings and outer tracks - mainshaft input
gear
6Mainshaft input gear bearing housing
7Cover plate
8Bolt - cover plate
9Selective shim
10Mainshaft input gear
11Oil filler/level plug
12Oil temperature switch - if fitted
13Bearings and outer tracks - intermediate gears
14Circlips
15Intermediate gears
16Bottom cover plate
17Bolt - bottom cover plate
18Selective spacer19Mainshaft oil seal
20Oil drain plug
21Main casing
22Intermediate shaft
23Locating dowel
24Detent ball - high/low selector
25Detent spring - high/low selector
26Detent plug - high/low selector
27Neutral warning switch - Automatic gearbox
only - North America and Japan
28Bolt - interlock solenoid cover - Automatic
gearbox only - North America and Japan
29Cover - interlock solenoid - Automatic gearbox
only - North America and Japan
30Belleville washer - Automatic gearbox only -
North America and Japan
31Interlock solenoid - Automatic gearbox only -
North America and Japan

TRANSFER BOX - LT230SE
DESCRIPTION AND OPERATION 41-5
Main casing components – Vehicles
from 03 model year
1Retaining plate
2Stake nut - intermediate shaft
3Bolt - retaining plate
4'O' rings - intermediate shaft
5Bearings and outer tracks - mainshaft input
gear
6Mainshaft input gear bearing housing
7Cover plate
8Bolt - cover plate
9Selective shim
10Mainshaft input gear
11Oil filler/level plug
12Bearings and outer tracks - intermediate gears
13Intermediate gears14Bottom cover plate
15Bolt - bottom cover plate
16Selective spacer
17Mainshaft oil seal
18Oil drain plug
19Main casing
20Intermediate shaft
21Locating dowel
22Detent ball - high/low selector
23Detent spring - high/low selector
24Detent plug - high/low selector
25Neutral warning switch - Automatic gearbox
only - North America and Japan