Land Rover Defender Workshop Rover Manual

							COOLINGSYSTEM
3
DESCRIPTION
ANDOPERATION
COOLANT
CIRCULATION
Operation When theengine isstarted fromcoldthethermostat
(2) prevents coolantcirculation throughtheradiator by
closing offthe tophose (6).During theengine warm
up period thewater pump (5)circulates coolanttothe
cylinders inthe crankcase andthrough separate ports
to the cylinder head.Atthe rear ofthe cylinder heada
proportion ofthe flow isdiverted throughaheater feed
pipe (16)tothe matrix ofthe heater unit(15). The
coolant isthen carried, viaaheater returnrail(14) and
hoses (7),back tothe water pump. Theremaining
coolant flowsthrough aby-pass hose(9)atthe
thermostat housingandback tothe water pump to
complete thefirst cycle.
When thenormal enginerunning temperature is
reached, thethermostat opens,closing offthe by-pass
hose (9).Coolant isthen circulated viathe tophose
(6) and through theradiator, whereitis cooled and
drawn fromtheradiator bottomhose(3)bythe water
pump (5).The coolant circulation throughthe
crankcase andcylinder headremains thesame.
Two bleed pipes(10)and(11) help control thesystem
pressure bypurging excessairand coolant tothe
expansion tankviathe Ypiece ejector(12). VISCOUS
FAN
DescriptionThe viscous driveunitforthe engine cooling fan,
provides ameans ofcontrolling thespeed ofthe fan
relative tothe running temperature ofthe engine. The
viscous unitisatype offluid coupling, whichdrives
the fanblades bymeans ofsilicone fluid.
1.Input (drive) member
2. Output (driven) member
3. Sensing mechanism (bi-metalcoil)
The fandrive hastobe engaged onlyperiodically,
between 5%and 10%, during normal operating
conditions, becausetheengine iscooled byram air
for most ofthe time.   
						

							26COOLING
SYSTEM
4 DESCRIPTION
ANDOPERATION
Operation To
engage anddisengage thefandrive thebi-metal
coil senses airtemperature behindtheradiator. When
a pre-determined temperatureisreached, thecoil
opens avalve (5)which allows fluidtoenter thedrive
area and,duetocentrifugal force,circulates tothe
annular drivearea.
There aretwo sets ofannular grooves (3),one inthe
drive clutch andtheother inthe drive body, aspecific
clearance beingprovided betweenthetwo sets of
grooves.
Viscous unitdisengaged (engineatnormal
running temperature)
1. Input (drive) member
2. Output (driven) member
3. Running clearance
4. Pump plate
5. Valve (closed)
6. Sensing mechanism (bi-metalcoil)
7. Fluid seal
8. Bearing, inputmember
9. Fluid chamber
10. Fluid reservoir When
thisclearance isfilled withviscous fluid,a
shearing action,caused bythe speed differential
between thetwo drive components, transmitstorque
to the fan. The fluid isthrown tothe outside ofthe unit
by centrifugal forcefromwhere itis recirculated tothe
reservoir (10)viathe pump plate(4)adjacent tothe
drive member.
If the engine speedisincreased theamount ofslip will
also increase tolimit themaximum fanspeed.
When theairtemperature fromtheradiator drops
sufficiently, thebi-metal coilcloses thevalve and
prevents fluidentering thedrive area. Thefluid thatis
in the drive areawillgradually pumpoutinto the
reservoir (10)andthefanwillreturn toan idle
condition.
Viscous unitengaged (hotrunning temperature)
Bi-metal coil(6)expanded, valve(5)open.   
						

							COOLINGSYSTEM
1
ADJUSTMENT
DRAIN
ANDREFILL COOLING SYSTEM
Service repairno-26.10.01
Draining
WARNING: DONOT remove capsorplugs
when theengine ishot. Thecooling
system ispressurised andpersonal
scalding couldresult.
1.Remove expansion tankfillercap.
2. Position aclean container underradiator if
coolant isto be reused.
3. Disconnect radiatorbottomhoseandallow
coolant todrain.
NOTE: Achassis undertray maybefitted
on some vehicle derivatives toconform to
legal requirements. Whenunder chassis
remove andrefit procedures arerequired, itmay
be necessary toremove theundertray and/or
integral accesspanels.
SeeCHASSIS ANDBODY,
Repair, Frontundertray
orSeeCHASSIS AND
BODY, Repair, Rearundertray
4.When expansion tankhasemptied remove
thermostat housingplugtoassist drainage.
5. Similarly whencoolant isbelow topofradiator,
remove radiator plug.
6. Fitradiator bottomhoseandfully tighten hose
clip. Refill
CAUTION:
Itis important thatthecorrect
procedure isfollowed whenrefilling or
topping upthe cooling systemtoavoid
trapping airinthe system.
7. Fill cooling systemwith50% -50% of
water/anti-freeze mixture
SeeLUBRICANTS,
FLUIDS ANDCAPACITIES, Information,
Recommended lubricantsandfluids
8.Fill through expansion tankuntilradiator isfull,
with level inexpansion tankthesame as
radiator.
NOTE: Careshould betaken toavoid
excess coolant spillage.
9.Fitplastic pluginradiator.
10. Add afurther 1litre (1.76 pints) ofcoolant into
expansion tankandallow tosettle.
11. Refit expansion tankcapand thermostat
housing plug.
12. Run engine atidle speed for5minutes.
13. Switch offengine andallow tocool.
14. Check thatcoolant inexpansion tankislevel
with topofindicator post.Topupifnecessary.    
						

							COOLINGSYSTEM
1
REPAIR
VISCOUS
COUPLING ANDFAN
Service repairno-26.25.19 -Viscous coupling
Service repairno-26.25.05 -Fan
Remove
NOTE: Theviscous coupling hasaLH
thread.
1. Disconnect battery.
2. Using special pulleyrestraining toolLRT-12-094
and special spanner LRT-12-093 unscrew
viscous coupling frompulley hubadaptor thread.
3.Remove viscouscoupling andfanfrom vehicle.
NOTE: Ifair conditioning isfitted, thefan
cowl willalso need removing,
SeeFan
cowl
, with theviscous fanunit.
4. Ifrequired, remove4screws andrelease
viscous unitfrom fanblade.
Refit
5. Fitviscous unittofan blades.
6. Ifapplicable, fitfan cowl.
See Fancowl
7.Carefully positionviscouscoupling andfitonto
pulley hubadaptor thread.
8. Using special pulleyretaining tool,spanner and
a suitable torquewrench, tightenassembly to
45
Nm (33lbf/ft).    
						

							26COOLING
SYSTEM
2 REPAIR
FAN
COWL
Service repairno-26.25.11
Remove 1. Disconnect battery.
2. Drain coolant.
SeeAdjustment, Drainand
refill cooling system.
3.Slacken retaining clipsandremove radiator top
hose.
4. Slacken retaining clipand remove tophose from
intercooler.
NOTE: Onvehicles fittedwithEGR system,
remove complete intercooler tophose
assembly.
5. Remove viscouscoupling andfan
See Viscous coupling andfan.
6.Remove 2nuts securing topoffan cowl.
7. Release expansion tankhose fromclips atbase
of fan cowl.
8. Lift and remove cowl.
NOTE: Onvehicles fittedwithair
conditioning, itwill benecessary to
remove thecowl andviscous fanunit
together toenable clearance ofthe compressor. Refit
9. Position fancowl.
10. Fitviscous fanunit.
See Viscous coupling
and fan
11.Fitexpansion tankhose intofancowl clips.
12. Secure topoffan cowl toradiator topcover.
13. Fitintercooler tophose.
14. Fitradiator tophose.
15. Refill cooling system.
SeeAdjustment, Drain
and refill cooling system
16.Reconnect battery.
FAN PULLEY
Service repairno-26.25.04.
Remove 1. Disconnect battery.
2. Remove viscousfanunit.
See Viscous
coupling andfan
3.Remove drivebelt.SeeELECTRICAL, Repair,
Auxiliary drivebelt
4.Unscrew 4bolts andremove pulleyfromadaptor
boss.
Refit 5. Fitfan pulley toadaptor boss.Tighten boltsto
25
Nm (18lbf/ft).
6.Fitdrive belt.SeeELECTRICAL, Repair,
Auxiliary drivebelt
7.Fitviscous fanunit.See Viscous coupling
and fan
8.Reconnect battery.   
						

							COOLINGSYSTEM
3
REPAIR
WATER
PUMP
Service repairno-26.50.01
Remove 1. Disconnect battery.
2. Drain cooling system.
SeeAdjustment, Drain
and refill cooling system
3.Remove radiatortophose.
4. Remove intercooler tophose.
5. Slacken waterpump andpower steering pump
pulley retaining bolts.
6. Remove drivebelt.
SeeELECTRICAL, Repair,
Auxiliary drivebelt
7.Unscrew flangenutand remove belttensioner.
8. Remove oilfiller capand remove rockercover
insulation.
9. Slacken retaining clipand disconnect hoseat
heater rail.
10. Unscrew 3bolts andremove waterpump pulley.
11. Unscrew 3bolts andremove powersteering
pump pulley.
12. Remove 8bolts securing waterpump, noting
location of3through boltsintocylinder block.
13. Withdraw pumpandgasket fromauxiliary
mounting bracket.
14. Clean allgasket material frommating faces.
Refit
15. Using newgasket, fitwater pump tomounting
bracket. Tightenboltsto
25Nm (18lbf/ft).
16. Fitpower steering pumppulley.
17. Fitwater pump pulley. Tighten boltsofboth
pulleys to
25Nm (18lbf/ft).
18. Fitdrive belt.SeeELECTRICAL, Repair,
Auxiliary drivebelt
19.Fithose atheater rail.
20. Fitrocker coverinsulation andoilfiller cap.
21. Fitdrive belttensioner. Tightenretaining nutto
45Nm (33lbf/ft).
22. Fitintercooler tophose.
23. Fitradiator tophose.
24. Refill cooling system.
SeeAdjustment, Drain
and refill cooling system
25.Reconnect battery.    
						

							26COOLING
SYSTEM
4 REPAIR
AUXILIARY
MOUNTING BRACKETANDGASKET
Service repairno-26.50.04
Remove 1. Disconnect battery.
2. Drain cooling system
SeeAdjustment, Drain
and refill cooling system
.
3. Remove radiatortophose.
4. Remove intercooler tophose.
5. Remove viscousfanunit.
See Viscous
coupling andfan
6.Remove fancowl.See Fancowl
7.Slacken powersteering pumppulley retaining
bolts.
8. Remove drivebelt.
SeeELECTRICAL, Repair,
Auxiliary Drivebelt
9.Unscrew 3bolts andremove powersteering
pump pulley.
10. Remove 4bolts securing powersteering pump
mounting bracket.
11. Lower pumpandbracket. Donot disconnect fluid
pipes.
12. Remove generator.
SeeELECTRICAL, Repair,
Generator
13. Unscrew retainingnutand remove drivebelt
tensioner.
14. Release hoseclipfrom bracket abovewater
pump. 15.
Disconnect bottomhose/heater returnhoseat
water pump andheater rail.
16. Disconnect by-passhosefromwater pump and
thermostat housing.
17. Remove 5bolts (onewithnut)andsingle
retaining nut,securing auxiliarymounting
bracket tocylinder block.
18. Withdraw mountingbracket,complete withwater
pump.
19. Remove gasketandclean mating faces.
Refit
20. Using 2slave studs, fitnew gasket.
NOTE: Allfixing boltsandnuts should be
tightened to
25Nm (18lbf/ft)unless
otherwise stated.
21. Locate mounting bracket,complete withwater
pump onslave studs andsecure with4other
fixings.
22. Remove slavestuds andfitremaining bolts/nuts.
23. Fitby-pass hosetothermostat housingand
water pump.
24. Fitbottom hose/heater returnhosetowater
pump andheater rail.
25. Fitheater hosecliptomounting bracket.
26. Fitdrive belttensioner. Tightennutto
45Nm (33
lbf/ft).
27. Fitgenerator.See ELECTRICAL, Repair,
Generator
Do not fitdrive beltatthis stage.   
						

							COOLINGSYSTEM
5
REPAIR
28.
Secure steering pumpandbracket toauxiliary
mounting bracket.
29. Fitsteering pumppulley.
30. Fitdrive belt
SeeELECTRICAL, Repair,
Auxiliary drivebelt
.
31. Fitfan cowl
See Fancowl.
32. Fitviscous fanunit
See Viscous coupling and
fan
.
33. Fitintercooler tophose.
34. Fitradiator tophose.
35. Refill cooling system.
SeeAdjustment, Drain
and refill cooling system
36.Reconnect battery. THERMOSTAT Service
repairno-26.45.01
Remove 1. Partially draincooling system, untilcoolant level
is below thermostat housing.
2. Disconnect tophose fromoutlet elbow.
3.Disconnect electricalconnections towater
temperature switch.
4. Unscrew 2bolts andremove outletelbow.
5. Withdraw thermostat. Note88°C rating of
thermostat.
6. Place thermostat inacontainer halffullofwater.
Heat water andobserve temperature atwhich
thermostat beginstoopen. Thermostat is
satisfactory ifitopens between 85°-8 9° C.
Refit 7. Fitthermostat withjiggle pin/vent holeupwards.
8. Secure outletelbow tothermostat housing.
Tighten boltsto
25Nm (18lbf/ft).
9.Fitwater temperature switchconnections.
10. Fittop hose tooutlet elbow.
11. Refill cooling system.
SeeAdjustment, Drain
and refill cooling system   
						

							26COOLING
SYSTEM
6 REPAIR
RADIATOR Service
repairno-26.40.01
Remove 1. Disconnect radiatorbottomhoseanddrain
cooling system.
SeeAdjustment, Drainand
refill cooling system
2.Disconnect radiatortophose.
3. Remove viscousfanunit.
See Viscous
coupling andfan
4.Remove fancowl.See Fancowl
5.Disconnect oilcooler pipes.Plugallconnections
to prevent oilspillage andingress ofdirt.
6. Disconnect topand bottom intercooler hoses.
7. Disconnect bleedhoseatradiator.
8. Remove 2bolts frombothsides securing
radiator mounting bracketstobonnet platform.
9. Lift and remove radiator/intercooler assembly
from vehicle.
10. Remove 2bolts frombothsides anddetach
radiator topcover fromsidecovers.
11. Liftand remove radiator fromintercooler andRH
side frame.
12. Check condition oflocating grommets inradiator
top cover andlower mounting bushes.Renewif
necessary. Refit
13. Position radiatorbetween intercooler andRH
side frame.
14. Fitradiator topcover toside covers.
15. Lower radiator/intercooler assemblyinto
position.
16. Secure radiator mounting bracketstobonnet
platform.
17. Fitradiator bleedhose.
18. Fittop and bottom intercooler hoses.
19. Fitoilcooler pipes.
20. Fitfan cowl
See Fancowl.
21. Fitviscous fanunit.
See Viscous coupling
and fan
22.Fitradiator tophose.
23. Fitradiator bottomhoseandrefill cooling
system.
See Adjustment, Drainandrefill
cooling system  
						

							COOLINGSYSTEM
7
REPAIR
EXPANSION
TANK
Service repairno-26.15.01
Remove 1. Position container tocollect coolant spillage.
2.Slacken retaining clipsanddisconnect both
hoses frombase ofexpansion tank.
3. Remove 3bolts securing expansion tankto
inside wingandmounting bracket.
4. Remove expansion tank.
Refit 5. Fitexpansion tanktoinside wingandmounting
bracket.
6. Fitboth hoses tobase oftank.
7. Check andtopupcooling system
See
SECTION 10,Maintenance, Underbonnet
maintenance