ISUZU TROOPER 1998 Service Repair Manual

6A– 98 ENGINE MECHANICAL
OIL PUMP ASSEMBLY
2
1
5
6
3
4
012RW097
Legend
(1) Flywheel
(2) Rear Plate (A/T)
(3) First Oil Pump Assembly(4) Second Oil Pump Assembly
(5) O-Ring (For first oil pump)
(6) O-Ring (For second oil pump)
REMOVAL
1. Disconnect battery ground cable
2. Lift up car
3. Drain engine oil
NOTE: Install drain plug with new gasket.
4. Flywheel
5. Rear Plate (A/T) or Flywheel Housing (M/T)
6. First Oil Pump Assembly and Second Oil Pump
Assembly
1) Remove oil pump assembly from cylinder block
and crankcase.
INSTALLATION
1. First oil pump assembly
1) Set O-ring to oil pump.
2) Install oil pump drive gear to the rear end of the
balance shaft RH.
3) Apply engine oil to pump gear, install pump gear
to rear end of cylinder block with specified
torque.Torque: 20 N·m (2.0 kg·m/14.5 lb ft)
2. Second oil pump assembly
1) Set O-ring to oil pump.
2) Install oil pump drive gear to the rear end of the
balance shaft LH.
3) Apply engine oil to pump gear, install pump gear
to rear end of crank case with specified torque.
Torque: 20 N·m (2.0 kg·m/14.5 lb ft)
3. Install rear plate (A/T) or flywheel housing (M/T)
Torque: 97 N·m (9.9 kg·m/72 lb ft)
4. Install flywheel
1) Apply engine oil to bolt and tighten with angular
tightening method.
First step: 59 N·m (6.0 kg·m/43 lb ft)
Second step: 60°to 90°

ENGINE MECHANICAL 6A– 99
OIL COOLER
For Europe1
2050R200001
Legend
(1) Oil Cooler Assembly
(2) Oil Filter Cartridge
OIL FILTER CARTRIDGE
REMOVAL
1. Place a receptacle beneath the oil filter to contain
the drained oil.
2. Remove the oil filter cartridge using filter wrench.
Filter wrench : 5-8840-0203-0
INSTALLATION
1, Lightly apply oil to the O-ring of oil filter cartridge.
2. Turn the new oil filter cartridge by hand until the
sealing face is fitted against the O-ring.
3. Use the filter wrench to turn the oil filter an
additional one and 1/8 turns.
4. Start the engine and check for oil leakage from oil
filter.

6A– 100 ENGINE MECHANICAL
REMOVAL
1. Disconnect battery ground cable
2. Drain engine coolant
3. Remove front exhaust pipe
4. Remove heat protector
5. Remove exhaust valve assembly
6. Oil cooler assembly
1) Remove water hoses from inlet and outlet pipe.
2) Put rag beneath side of oil cooler to prevent oil
leaking.
3) Remove fixing bolts and oil cooler assembly.
INSTALLATION
1. Oil Cooler
1) Tighten oil cooler fixing bolt to the specified
torque and connect water hose.
Torque: 29 N·m (3.0 kg·m/22 lb ft)
2. Exh. Valve Assembly
1) Install exhaust valve assembly with gasket and
tighten fixing bolts to the specified torque.
Torque: 27 N·m (2.7 kg·m/20 lb ft)
3. Heat Protector
4. Front Exhaust Pipe
1) Install front exhaust pipe and tighten fixing bolts
to the specified torque.
Exh. Valve Side: 67 N·m (6.8 kg·m/50 lb ft)
Intermediate Pipe Side: 43 N·m (4.4 kg·m/32 lb ft)
5. Fill engine coolant.
6. Connect battery ground cable.
7. Start engine and check for oil and water leakage
carefully.

ENGINE COOLING 6B – 1
ENGINE COOLING
CONTENTS
General Description . . . . . . . . . . . . . . . . . . 6B–2
On-Vehicle Service . . . . . . . . . . . . . . . . . . . 6B–6
Water Pump . . . . . . . . . . . . . . . . . . . . . . 6B–6Thermostat . . . . . . . . . . . . . . . . . . . . . . . 6B–7
Radiator . . . . . . . . . . . . . . . . . . . . . . . . . 6B–9
Drive Belt Adjustment . . . . . . . . . . . . . . . 6B–11

6B – 2 ENGINE COOLING
Legend
(1) Turbocharger
(2) Thermostat
(3) Reservoir Tank
(4) Radiator
(5) Bypass(6) Oil Cooler
(7) Cooling fan
(8) Water Pump
(9) Thermo Valve
(10) Car Heater
(11) EGR Cooler
GENERAL DESCRIPTION
COOLANT FLOW
1
6
9
9
For Europe only
10
8
4
32
5
7
11
032R200001
The cooling system is a pressurized coolant forced
circulation type which consists of water pump,
thermostat, cooling fan, radiator and other components. The circulating coolant cools the lubricating oil in the oil
cooler and turbocharger.

ENGINE COOLING 6B – 3
WATER PUMP
The coolant pump is a centrifugal impeller type and is
driven by V type drive belt.
Legend
(1) Roller Bearing
(2) Ball Bearing
(3) Seal Unit
THERMOSTAT
The thermostat is a wax pellet type with a jiggle valve
and is installed in the thermostat housing.
Legend
(1) Bolt
(2) Thermostat Housing
(3) Thermostat
(4) Intake Manifold
RADIATOR
The radiator is a tube type with corrugated fins. In order
to raise the boiling point of coolant, the radiator is fitted
with a cap in which the valve is operated under the
pressure.
1
3 2
PCD 60
A06RW024
1
2
3
4
032RW002
110RS001

6B – 4 ENGINE COOLING
ANTI-FREEZE SOLUTION
•Relation between Mixing ratio and Freezing point
Freezing temperature of the engine coolant varies
with the ratio of anti-freeze solution in water.
Proper mixing ratio can be determined by refering
to the chart. Supplemental inhibitors or additives
claiming to increase cooling capability that have not
been specifically approved by Isuzu are not
recommended for addition to the cooling system.
•Calculation of mixing ratio
Mixing ratio (%)
=Anti-freeze solution (Lit/qt.)
×100
Anti-freeze solution (Lit/qt.) + Water (Lit/qt.)
For example
In case total coolant capacity = 10
l
It is necessary to mix about 35% anti-freeze
solution at ambient temperature minus 20°C.
Capacity of anti-freeze solution:
35
×10 = 3.5
l100
Water capacity: 10
l– 3.5 l= 6.5 l
Therefore, you prepare the water 6.5 land anti-
freeze solution 3.5
l, then mix them to get total
10
lcoolant.•Mixing ratio
Check the specific gravity of engine coolant in the
cooling system in temperature ranges from 0°C to
50°C using a suction type hydrometer, then
determine the density of the coolant by referring to
the table at below.
-1010 0
Freezing Temperature(°C)
20 30 Antifreeze Solution Density(%)
40 50
-20
-30
-40
B06RW018
1,100
20 10 30 4060%
50%
40%
20%
10%
30%
Antifreeze Solution Temperature(°C) 50 60 70 0
Specific Gravity
1,090
1,080
1,070
1,060
1,050
1,040
1,030
1,020
1,010
1,000
B06RW017

ENGINE COOLING 6B – 5
ENGINE COOLANT CHANGE
PROCEDURE
1. To change engine coolant, make sure that the
engine is cool.
WARNING:
When the coolant is heated to a high temperature,
be sure not to loosen or remove the radiator cap.
Otherwise you might get scalded by hot vapor or
boiling water. To open the radiator cap, put a piece
of thick cloth on the cap and loosen the cap slowly
to reduce the pressure once the coolant has
become cooler.
2. Open radiator cap and drain the cooling system by
loosening the drain valve on the radiator and on the
cylinder body.
NOTE: For best results it is suggested that the engine
cooling system be flushed at least once a year. It is
advisable to flush the interior of the cooling system
including the radiator before using anti-freeze
(ethylene-glycol based).
Replace damaged rubber hoses as the engine anti-
freeze coolant is liable to leak out even minor cracks.
Isuzu recommends using Isuzu genuine anti-freeze
(ethylene-glycol based) or equivalent, for the cooling
system and not add any inhibitors or additives.
CAUTION:
A failure to correctly fill the engine cooling system
in changing or topping off coolant may sometimes
cause the coolant to overflow from the filler neck
even before the engine and radiator are completely
full.
If the engine runs under this condition, shortage of
coolant may possibly result in engine overheating.
To avoid such trouble, the following precautions
should be taken in filling the system.
3. To refill engine coolant, pour coolant up to filler neck
using a filling hose which is smaller in outside
diameter than the filler neck. Otherwise air between
the filler neck and the filling hose will block entry,
preventing the system from completely filling up.
4. Keep a filling rate of 9 liter/min. or less. Filling over
this maximum rate may force air inside the engine
and radiator.
And also, the coolant overflow will increase, making
it difficult to determine whether or not the system is
completely full.
5. After filling the system full, pull out the filling hose
and check to see if air trapped in the system is
dislodged and the coolant level goes down. Should
the coolant level go down, repeat topping-off until
there is no more drop in the coolant level.
6. Directly after filling the radiator, fill the reservoir to
the maximum level.
7. Install and tighten radiator cap and start the engine.
After idling for 2 to 3 minutes, stop the engine and
reopen radiator cap. If the water level is lower,
replenish.WARNING:
When the coolant is heated to a high temperature,
be sure not to loosen or remove the radiator cap.
Otherwise you might get scalded by hot vapor or
boiling water. To open the radiator cap, put a piece
of thick cloth on the cap and loosen the cap slowly
to reduce the pressure once the coolant has
become cooler.
8. After tightening radiator cap, warm up the engine at
about 2,000 rpm.
Set heater adjustment to the highest temperature
position, and let the coolant circulate also into
heater water system.
9. Check to see the thermostat has opened by the
needle position of a water thermometer, conduct a
5-minute idle again and stop the engine.
10. When the engine has been cooled, check filler neck
for water level and replenish if required. Should
extreme shortage of coolant be found, check the
coolant system and reservoir tank hose for leakage.
11. Fill the coolant into the reservoir tank up to “MAX”
line.

6B – 6 ENGINE COOLING
REMOVAL
1. Drain coolant.
2. AC Generator Drive Belt
1) Loosen AC Generator mounting bolt, adjust
plate lock bolt, and remove the drive belt.
3. Cooling Fan Assembly
1) Remove lock nut and take out cooling fan
assembly with cooling fan clutch.
4. Water Pump Assembly
INSPECTION
Make necessary repair and parts replacement if
excessive wear or damage is found during inspection.
Should any of the following problems occur, the entire
water pump assembly must be replaced.
1) Cracks in the water pump body
2) Coolant leakage from the seal unit
3) Excessive play in radial direction or abnormal noise
4) Excessive play in thrust direction
Limit : 0.2mm (0.008in) or less
5) Cracks or corrosion in the impeller
INSTALLATION
1. Gasket
1) Set gasket to gear case.
2. Water Pump Assembly
1) Install water pump assembly, and tighten to
specified torque.Torque: 20 N·m (2.0 kg·m/14.5 lb ft)
3. Cooling Fan Assembly
1) Install cooling fan assembly, and tighten to
specified torque.
Torque: 8 N·m (0.8 kg·m/5.8 lb ft)
4. AC Generator Drive Belt
1) Install AC Generator drive belt and adjust belt
tension.
Torque: 40 N·m (4.1 kg·m/29.7 lb ft)
For ACG to bracket
20 N·m (2.0 kg·m/14.5 lb ft)
For ACG to adjust plate
5. Fill coolant to specified capacity.
12
Legend
(1) Fan Pulley
(2) Water Pump Assembly
030RW009
ON-VEHICLE SERVICE
WATER PUMP

ENGINE COOLING 6B – 7
THERMOSTAT
REMOVAL
1. Disconnect battery ground cable.
2. Drain coolant from the radiator and engine.
3. Thermostat housing
1) Remove mounting bolt and remove thermostat
housing together with radiator hose.
4. Gasket
5. Thermostat
INSPECTION
Make necessary repair and parts replacement if
excessive wear or damage is found during inspection.
Submerge the thermostat assembly in the water.
Place wooden blocks on the bottom of the water
container.
Do not heat the thermostat directly.
Gradually increase the water temperature. Stir the
water so that the entire water is the same temperature.
1) Make sure that valve begins to open at the
specified temperature.
Valve Opening Temperature: 85°C (185°F)
2) Make sure that valve opens fully at the specified
temperature.
Valve Full Open Temperature: 100°C (212°F)
1
2
3
4
Legend
(1) Bolt
(2) Thermostat Housing
(3) Thermostat
(4) Intake Manifold
035RW002
031RS003