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
REPAIR
3.Use LRT-12-093 to prevent coolant pump pulley
from turning and using LRT-12-094, unscrew
viscous coupling from water pump.
NOTE: Nut securing viscous unit to water
pump has a right hand thread. Release by
turning anti-clockwise when viewed from
front of viscous unit.
4.Remove fan and coupling assembly.
Do not carry out further dismantling if component
is removed for access only.
NOTE: Mark fan with reference to assist
refitting.
5.Remove 4 Allen screws securing blades to
coupling. Remove coupling.
6.Remove serpentine drive belt.
7.Remove pulley fixings, remove pulley.Refit
8.Clean fan blades and mating faces.
9.Fit fan blades to coupling. Secure with screws.
Tighten to
24 Nm.
10.Using LRT-12-093 and LRT-12-094, fit fan
assembly to pump. Tighten to
56 Nm.
11.Fit cooling fan upper cowl. Secure with clips.
12. 4.0 V8 only:Fit coolant hose to cooling fan upper
cowl.
13.Fit serpentine drive belt.
14.Fit pulley fixings, remove pulley.
15.Reconnect battery negative lead.
26COOLING SYSTEM
6
REPAIR WATER PUMP
Service repair no - 26.50.01
Remove
WARNING: Disconnect battery negative
terminal to prevent engine being started
before removing or adjusting drive belts.
1.Drain engine cooling system.
See Adjustment,
Coolant
2.Remove fan blades and pulley.See Viscous
Coupling, Fan Blades, Pulley and Fan Cowl
3.Disconnect inlet hose from water pump.
4.Remove water pump bolts.
5.Remove water pump and joint washer.
Refit
6.Lightly grease new joint washer, position on
timing cover.
7.Clean threads of all long bolts and coat with
Loctite 572 thread lubricant-sealant.
8.Locate water pump in position. Tighten
remaining water pump housing bolts evenly to
28 Nm.
9.Reverse removal procedure. 1 to 3.
10.Check for coolant leaks around all hose
connections and joint faces.
30MANIFOLD AND EXHAUST SYSTEM
8
REPAIR 6.Disconnect oxygen sensor multiplug.
7.Release multiplug from bracket on thermostat
housing.
8.Release harness from cable tie.
9.Remove drive belt.
10.Remove 2 front bolts securing generator to
mounting bracket.
11.Remove 2 rear bolts securing generator to
mounting bracket.
12.Move generator from mounting bracket and
place aside.
13.Remove exhaust manifold heat shield.
14.Remove dipstick and bolt securing dipstick tube
to coolant rail.
15.Remove dipstick tube from cylinder block.16.Remove 3 bolts and 2 nuts securing exhaust
manifold to cylinder head.
17.Release coolant rail bracket from manifold studs.
18.Remove exhaust manifold and discard gasket.
Refit
NOTE: For torque values.See
Specifications, torque, Torque Values
19.Clean mating faces of exhaust manifold and
cylinder head.
20.Fit new manifold gasket and align exhaust
manifold to cylinder head.
21.Position coolant rail bracket to manifold studs.
22.Fit manifold nuts and bolts, tighten to the correct
torque in the order shown.
23.Secure oxygen sensor multiplug to bracket.
24.Connect oxygen sensor multiplug.
25.Fit new manifold flange gasket and align exhaust
front pipe to manifold.
26.Fit nuts and tighten diagonally to the correct
torque.
27.Tighten exhaust downpipe to silencer box nuts
to the correct torque.
28.Position generator to mounting bracket.
29.Fit and tighten 4 generator securing bolts.
30.Refit drive belt.
STEERING
1
DESCRIPTION AND OPERATION DESCRIPTION
The power assisted steering system incorporates a
compression joint in the lower shaft, designed to
collapse on impact and for certain countries, an air
bag located in the centre of the steering wheel.
The mis-alignment of the upper steering column with
the steering box and the inclusion of two universal
joints and a compression joint in the lower shaft, is
also designed to prevent frontal impact moving the
column toward the driver.
The steering box is located behind the first cross
member of the chassis and is connected to the road
wheels by the drag link and track rod. An hydraulic
damper absorbs shocks in the steering, caused by
road wheel deflections when operating on rough
terrain.Power steering system
The power steering system comprises a hydraulic
pump which is belt driven from the engine and
supplied with fluid from a reservoir that also acts as a
cooler.
The steering box houses a self neutralizing rotary
valve which is part of the worm/valve assy and a
hydraulic piston/rack to assist the mechanical
operation.
The rotary valve which is operated by movement of
the steering wheel, directs fluid pressure to the
appropriate side of the hydraulic piston/rack to provide
assistance.
Power steering system
1. Hydraulic pump
2. Fluid reservoir
3. Steering box
4. Upper column
5. Universal joints
6. Lower shaft
7. Compression joint
8. Drag link
STEERING
7
DESCRIPTION AND OPERATION Pump and regulator valve operation
The pump which is belt driven from the engine is an
eccentric roller type and also houses the pressure
regulator and flow control valve. The pressure is
controlled by a spring loaded ball valve 3 which is
housed inside the flow control valve piston 4.
No demand for assistance High flow through box -
Low pressure
With no demand for assistance as illustrated in
RR3568M the rotary valve in the steering box acts as
a pressure relief valve, allowing fluid A to flow freely
through the steering box and back to the reservoir and
pump inlet B.
No demand for assistance
1. Reservoir
2. Pump
3. Pressure control ball valve and spring
4. Flow control valve and spring
5. Press fit plug (ball bearing)
6. Restrictor
The ball plug item 5 is pressed into the valve 4
during manufacture and determines the opening
pressure of pressure relief valve 3.No flow, through box - High pressure
When the steering is turned, the rotary valve
effectively stops all fluid flow through the steering box,
thus causing an increase in pressure A. This increase
in pressure is felt in the flow control valve spring
chamber where, at a pre-determined pressure the
relief valve 3 will open and allow the pressure to
escape. The fall in pressure in the flow control spring
chamber, allows the flow control valve to move to the
right, which in turn allows pump output A to escape
directly into the pump inlet B, as seen in RR3569M.Assistance demanded
As soon as the steering wheel is released after
making a turn, the system reverts to the condition
seen in RR3568M and the road wheels are returned
to the straight ahead position by the mechanical
steering geometry.
In the event of any hydraulic failure steering control
though heavy, will be maintained through the
mechanical components in the steering box.
STEERING
1
FAULT DIAGNOSIS INSUFFICIENT POWER ASSISTANCE
1.Is fluid level correct?
YES - go to 3.
NO - Fill/bleed sytem
2.Is problem a leak?
YES - Diagnose.
See Power Steering Fluid
Leaks
NO - continue
3.Is drive belt tension correct?
YES - go to 5.
NO - retension.
See ENGINE, Repair, Drive
Belt
4.Is problem resolved?
YES - end
NO - continue
5.Carry out pressure test at idle and 1000 rev/min.
See Power Steering System - Test
6.Is correct pressure achieved?
YES - steering box defective
Not at any speed go to 9.
Not at idle go to 7.
7.Is idle speed correct?
YES- Goto8.
NO - Correct idle speed -
If 3.9
See ENGINE TUNING DATA,
Information, Engine 3.9 V8i
If TdiSee ENGINE TUNING DATA,
Information, 300 Tdi Engine
If MpiSee ENGINE TUNING DATA,
Information, Engine - Mpi - 2.0 Litre
8.Is problem resolved?
YES - end
NO - go to 9.
9.Bypass steering box using adaptor tap
LRT-57-001
10.Is correct pressure obtained?
YES - defective steering box
NO - defective steering pump
CAUTION: Do not hold steering wheel on
full lock for more than 30 seconds in any
one minute to avoid overheating fluid and
possibly damaging seals.
NOTE: 1. Excessive pressure in the
system is almost always caused by a
faulty relief valve in the PAS pump.
NOTE: 2. Insufficient pressure in the
system is usually caused by low fluid level
or PAS pump drive belt slip, or one of the
following: PAS system leaks, faulty PAS pump
relief valve, fault in steering box valve and worm
assembly, leak at piston in steering box, worn
components in PAS pump or box.
57STEERING
2
FAULT DIAGNOSIS POWER STEERING SYSTEM - TEST
NOTE: If steering lacks power assistance.
Check pressure of hydraulic pump before
fitting new components. Use fault
diagnosis chart to assist in tracing faults.
A. Steering box.
B. Steering pump.
C. Existing hose, steering box to pump.
D. Hose LRT-57-030.
E. Test adaptor LRT-57-001.
F. Pressure gauge LRT-57-005.
G. Thread adaptor LRT-57-004.
H. Thread adaptor LRT-57-022.Procedure
1.A hydraulic pressure gauge and test adaptor is
used to test power steering system. This gauge
is able to measure 140 kgf/cm
2. The maximum
power steering system pressure is 77 kgf/cm2.
2.Some fault conditions of hydraulic pump may
obtain pressures up to 105 kgf/cm
2. Pressure on
gauge is same pressure being exerted upon
steering wheel. When testing, turn steering
wheel gradually while reading pressure gauge.
3.Check and maintain maximum fluid level of
reservoir.
4.Examine power steering units and connections
for leaks. All leaks must be rectified before
attempting to test the system.
5.Check steering pump drive belt tension.
See
ENGINE, Repair, Drive Belt
6.Assemble test equipment and fit to vehicle, as
shown in RR3959M.
7.Open tap of adaptor.
8.Bleed system, take care not to overload
pressure gauge.
9.With system in good condition, pressures should
be:
(A) Steering wheel held on full lock and engine
running at 1,000 rev/min, 70 to 77 kgf/cm
2.
(B) Steering wheel held on full lock and engine
idling, 28 kgf/cm
2.
Checks should be carried out on both full lock
positions.
CAUTION: Do not maintain this pressure
for more than 30 seconds in any one
minute to avoid overheating fluid and
possibly damaging seals.
10.Release steering wheel and with engine idling.
Pressure should read below 7 kgf/cm
2.
11.If pressures differ to those given a fault exists.
12.To determine if fault is steering box or pump.
Close adaptor tap for a maximum five seconds.
13.If gauge does not register specified pressure,
pump is faulty.
14.Fit a new pump, bleed system and repeat test. If
low pressure or a substantial imbalance exists,
fault is in steering box valve and worm
assembly.