heater LAND ROVER DISCOVERY 1995 Owner's Manual

Tdi
1
DESCRIPTION AND OPERATION ENGINE COOLING
Description
The Tdi engine uses a pressurized cooling system
and cross flow radiator which is supplied from a
separate header tank. The radiator assembly is in
three sections. The largest section is for engine
coolant and the other two sections which are cast in
aluminium, are the engine oil cooler and the turbo
charger intercooler.
A belt driven viscous fan and centrifugal water pump
is located in the front of the cylinder block. Hot coolant
is supplied to the heater through hoses. Two small
diameter air purge hoses connect the top of the
radiator and cylinder head water gallery, to the header
tank.
Coolant circulation (engine cold)
1. Cross flow radiator
2. Header tank
3. Viscous fan
4. Heater hoses
5. By pass hose and engine thermostat
6. Air purge hoses
7. Coolant pumpCOOLANT CIRCULATION
Operation
When the engine is started from cold the thermostat
prevents any coolant circulation through the radiator
by closing off the top hose. During the engine warm
up period, the water pump, pumps coolant towards
the rear of the cylinder block around each of the
cylinders. Coolant as it is heated rises through ports in
the cylinder block and head gasket, into the cylinder
head.The coolant flows forwards to the thermostat,
by-pass port and radiator top hose connection.
Start from cold (thermostat closed)
While the thermostat is closed, coolant circulates
around the cylinder block and cylinder head via the
by-pass.
Engine warm (thermostat open)
When the engine reaches normal running temperature
the thermostat closes off the by-pass and opens the
flow to the top of the radiator.

Tdi
1
FAULT DIAGNOSIS ENGINE OVERHEATING
Before conducting any cooling system diagnosis:
See
Description and operation, Engine Cooling
1.Is coolant level correct?
NO - Allow engine to cool, top up level to
expansion tank seam.
YES - Continue.
2.Is drive belt tension correct?
NO -
See ENGINE, Repair, Compressor
Drive Belt
YES - Continue.
3.Is coolant in radiator frozen?
YES - Slowly thaw and drain system.
See
Adjustment, Coolant
NO - Continue.
4.Is air flow through radiator restricted or blocked?
YES - Apply air pressure from engine side of
radiator to clear obstruction.
NO - Continue.
5.Are there any external leaks, from water pump,
engine gaskets, fast idle thermostat or the heater
unit?
YES - Investigate and rectify.
See Adjustment,
Coolant
NO - Continue.
6.Are fan blades fitted correct way round, concave
side towards engine?
NO - Rectify.
YES - Continue
7.Is viscous unit operating correctly?
See
Description and operation, Viscous Fan
NO - Renew.See Repair, Viscous
Coupling, Fan Blades, Pulley and Fan
Cowl
YES - Carry out a pressure test on radiator cap
and system. Check thermostat type,
operation and correct fitting.
See Repair,
Thermostat
If pressure test leads you to suspect coolant
leakage across gaskets, go to check 10,
otherwise: Continue.8.Are the air conditioning fans operating correctly?
See Electrical Trouble Shooting Manual.
NO - Rectify.
YES - Continue.
9.Is temperature sender and gauge giving
accurate readings?
NO - Sustitute parts and compare readings.
YES - Continue.
10.Carry out cylinder pressure test to determine if
pressure is leaking into cooling system causing
over pressurising and loss of coolant.
If problem is not diagnosed, check the coolant system
for engine oil contamination and engine lubrication
system for coolant contamination.
If only the coolant system is contaminated suspect a
cylinder head gasket.
If both systems are contaminated, suspect the
radiator.
If only the lubrication system is contaminated with
coolant, suspect leakage past cylinder liner seals or
cylinder head gasket.

V8i
1
DESCRIPTION AND OPERATION ENGINE COOLING
Description
The V8i engine uses a pressurised cooling system
and cross flow radiator which is supplied from a
separate header tank. The coolant radiator also
incorporates a section at the left hand end for cooling
the transmission oil and a section at the other end for
cooling the engine oil.The belt driven viscous fan and centrifugal water
pump is located in the engine front cover with ports for
circulation of coolant to both banks of cylinders and
cylinder heads. Coolant returns to the top of the
radiator via ports in the inlet manifold where the
thermostat is mounted horizontally.
Coolant also circulates through the vehicle heating
system and is used to heat air entering the inlet
manifold plenum chamber.
Coolant circulation (engine hot)
1. Cross flow radiator
2. Header tank
3. Viscous fan and water pump
4. Heater pipes
5. Plenum chamber connection
6. Thermostat

26COOLING SYSTEM
2
DESCRIPTION AND OPERATION COOLANT CIRCULATION
Operation
When the engine is started from cold the thermostat
prevents any coolant circulation through the radiator
by closing off the top hose. During the engine warm
up period, the water pump, pumps coolant around the
cylinders to the rear of the cylinder block along the
main galleries in both cylinder banks. At the rear of
the cylinder block the coolant rises through a large
port in each cylinder head/block joint face, and then
flows forward to connect with ports at the front of the
inlet manifold. From the manifold the coolant is carried
by an external pipe to the heater unit and from the
heater through another external pipe to the pump
inlet.The coolant circulation through the cylinder block and
heads, does not change when normal running
temperature is reached and the thermostat opens. But
with the thermostat open, coolant flows through the
top hose to the radiator where it is cooled and drawn
back into the pump via the bottom hose.

V8i
1
FAULT DIAGNOSIS ENGINE OVERHEATING
Before conducting any cooling system diagnosis:
See
Description and operation, Engine Cooling
1.Is coolant level correct?
NO - Allow engine to cool, top up level to
expansion tank seam.
YES - Continue.
2.Is drive belt tension correct?
NO -
See ENGINE, Repair, Drive Belt -
Check Tension
YES - Continue.
3.Is ignition timing correct?
NO -
See ELECTRICAL, Adjustment,
Ignition Timing
YES - Continue.
4.Is coolant in radiator frozen?
YES - Slowly thaw and drain system.
See
Adjustment, Coolant Requirements
NO - Continue.
5.Is air flow through radiator restricted or blocked?
YES - Apply air pressure from engine side of
radiator to clear obstruction.
NO - Continue.
6.Are there any external leaks, from water pump,
engine gaskets or the heater unit?
YES - Investigate and rectify.
See Adjustment,
Coolant Requirements
NO - Continue.
7.Are fan blades fitted correct way round, concave
side towards engine?
NO - Rectify.
YES - Continue.8.Is viscous unit operating correctly?
See
Description and operation, Viscous Fan
NO - Renew.See Repair, Viscous
Coupling, Fan Blades, Pulley and Fan
Cowl
YES - Carry out a pressure test on radiator cap
and system. Check thermostat type,
operation and correct fitting
See Repair,
Thermostat
If pressure test leads you to suspect coolant
leakage across gaskets, go to check 11,
otherwise: Continue.
9.Are the air conditioning fans operating correctly?
See Electrical Trouble Shooting Manual.K5
NO - Rectify.
YES - Continue.
10.Is temperature sender and gauge giving
accurate readings?
NO - Substitute parts and compare readings.
YES - Continue.
11.Carry out cylinder pressure test to determine if
pressure is leaking into cooling system causing
over pressurising and loss of coolant.
If problem is not diagnosed, check the coolant system
for engine oil contamination and engine lubrication
system for coolant contamination.
If the coolant only, or both systems are contaminated,
suspect cylinder head gaskets or radiator.
If only the lubrication stystem is contaminated with
coolant, suspect inlet manifold or front cover gaskets.

26COOLING SYSTEM
2
ADJUSTMENT 3.Disconnect bottom hose from radiator. Drain
coolant into a clean container. Reconnect bottom
hose, re-tighten hose clamp.
NOTE: It is not possible to drain all coolant
retained in heater system. It is not
desirable to flush through system, after
draining.
4.Remove engine drain plugs, one each side of
cylinder block, beneath exhaust manifolds. Drain
coolant, refit and tighten plugs.
5.Pour correct solution of water and anti-freeze
into expansion tank until radiator is full.
6.Start engine, run it until normal operating
temperature is attained, topping up as
necessary.
7.Refit radiator filler plug and 'O' ring, with new 'O'
ring if required. Tighten to
6 Nm.
8.Fit expansion tank filler cap.
9.Allow engine to cool, check coolant level. Finally
top up expansion tank until level reaches seam
of expansion tank.

26COOLING SYSTEM
2
REPAIR RADIATOR
Service repair no - 26.40.01
Remove
1.Disconnect battery negative lead.
WARNING: Do not carry out the next
instruction until the coolant is cool to
avoid personal injury from scalding.
2.Slacken clip and release bottom hose from
radiator, allow coolant to drain into a suitable
container
3.Slacken clip and release bottom hose from
radiator rail.
4.Slacken clip and release top hose from radiator.
5.Release air cleaner to throttle housing hose from
securing brackets.
6.Slacken clip and release bypass hose from
radiator.
7.Slacken clip and release top expansion hose
from radiator.
8.Remove 2 bolts securing radiator side support
brackets.
9.Collect L.H. support bracket and position R.H.
support bracket aside.
10.Slacken clip and release heater hose from
radiator rail.
11.Disconnect 2 multiplugs from cooling fan
assemblies.

30MANIFOLD AND EXHAUST SYSTEM
4
REPAIR EXHAUST MANIFOLD - Tdi
Service repair no - 30.15.10
Remove
1.Disconnect battery negative lead.
2.Remove heat shield from rear of air intake
manifold.
3.Release dip stick tube from cylinder block.
4.Disconnect the intake hose from the manifold.
5.Remove the two bolts and two nuts securing the
intake manifold to the cylinder head and
withdraw the inlet manifold.
6.Remove air filter inlet pipe to turbo unit.
7.Remove intercooler pipe from turbo to
intercooler.
8.Disconnect the EGR pipe from the inlet manifold
hose.
9.Remove the three fixings at the exhaust pipe
flange.
10.Release the turbo charger oil pipes from the
cylinder block.
11.Remove the turbo boost pipes.
12.Remove seven bolts securing the exhaust
manifold, release the heater rail and remove the
manifold gasket, complete with turbo unit.
13.Remove four bolts and disconnect diaphragm
rod from manifold, and remove turbo charger if
necessary.
Refit
14.Reverse removal procedure. 1 to 12. Use a new
manifold and exhaust flange gaskets.
15.Reconnect battery negative lead. Start engine
and check for leaks.

41TRANSFER GEARBOX
4
REPAIR SHIFTLOCK SOLENOID/NEUTRAL SWITCH
Service repair no - 41.10.63/64
This is sited on top of the transfer gearbox. Access to
the component is gained through the transmission
tunnel aperture.
Remove
1.Disconnect battery negative lead.
2.Remove centre console.
See CHASSIS AND
BODY, Repair, Centre Console
3.Remove rear passenger heater air ducts.
4.Remove insulation pad.
5.Remove four screws and remove main gear
lever assembly.
6.Drill out rivets and remove tunnel blanking plate.
7.Disconnect solenoid multiplug.
8.Remove four retaining bolts and remove shiftlock
solenoid cover.
9.Remove solenoid and spring washer.
10.Clean joint sealant from mating faces.
KEY
1. Gearlever
2. Transmission tunnel aperture
3. Transfer gearbox
4. Bolt
5. Switch
6. Solenoid
7. Electrical connectionsRefit
1.Apply Hylosil or equivalent sealant to mating
faces.
2.Ensure solenoid plug lead is located in cover
recess.
3.Reverse removal procedure.
4.Fit four solenoid bolts. Tighten to
9Nm.
Neutral switch, audible alarm
1.Disconnect neutral switch electrical plug.
2.Remove neutral switch from transfer box.
Refit
3.Apply Hylomar PL32/L20 or SL500 sealant to
neutral switch.
4.Reverse removal procedure.
5.Switch - Tighten to
25Nm.

75SUPPLEMENTARY RESTRAINT SYSTEM
14
REPAIR AIRBAG HARNESS
Service repair no - 86.70.63
Remove
1.Remove driver's airbag.
See driver's airbag
module.
2.Remove passenger's airbag.See passenger's
airbag module.
3.Remove dash panel assembly.See CHASSIS
AND BODY, Repair, dash panel assembly
4.Remove heater blower unit.See HEATING
AND VENTILATION, Repair, blower motor
unit - heater and air conditioning.
5.Remove heater and cooler unit.See AIR
CONDITIONING, Repair, heater and cooler
unit
Pre 97 MY
6.Remove 3 screws securing expansion tank and
position expansion tank aside.
7.Disconnect multiplug from each crash sensor.
8.Release airbag harness from clips and ties along
the bulkhead and each valance.
9.Displace airbag harness grommet to inside of
bulkhead and feed harness through bulkhead.
All Models
10.Disconnect multiplug from airbag control unit.
11.Release airbag harness from under carpet.
12.Release ties securing harness along toeboard.
13.Disconnect steering wheel airbag multiplug.
14.Release airbag harness from driver's side and
remove.
Refit
15.Reverse removal procedure.
CAUTION: Ensure harness is correctly
routed in harness protector and that all
securing clips and ties are correctly
engaged and harness is undamaged. Ensure all
connections are fully engaged and retained by
their latches.