1998 ISUZU TROOPER heater

4JG2-NA/4JG2-TURBO ENGINE 6A 2Ð 27
REMOVAL
Preparation
·Remove battery. (two batteries for cold area)
·Disconnect window washer hose, and remove
engine hood.
·Drain coolant.
·Space stand and front right tire.
1. Radiator Hose : Upper
·Disconnect upper radiator hose from engine side.
2. Air Cleaner Cover & Air Duct
3. Intercooler Assembly (4JG2-T Only)
·(Refer to intercooler removal steps in this section)
4. Oil Level Gauge Guide Tube
5. P/S Pump
·Loosen P/S pump fixing bolts and adjusting bolt
and remove two drive belts.
·Remove two fixing bolts (front side). A fixing nut
(rear side) and support P/S pump asm with oil
hoses by tying to body side.
6. A/C Compressor Assembly
·Remove A/C compressor fixing bolt (rear under
side of compressor) by using a long extension bar
at under side of wheel arch.
·Disconnect magnetic clutch harness connector.
·Remove fixing bolts (upper and front lower side of
compressor) and set A/C compressor asm with
pipe line on battery carrier.
7. Water Hose; CSD
·Disconnect CSD water hoses from heater hose
side.
8. Engine Harness
·Disconnect five harness connectors from units on
thermostat housing.
9. Heater Hose: Rear Side
·Disconnect heater hose from heater pipe.
10. Water Bypass Hose
·Disconnect water bypass hose from water pump.
11. Water Inlet Hose: Turbo (4JG2-T Only)
·Disconnect from water outlet pipe of engine.
12 Water Outlet Hose: Turbo (4JG2-T Only)
·Disconnect from water inlet pipe of engine.
13 Oil Feed Pipe: Turbo (4JG2-T Only)
·Remove two joint bolts (from turbocharger and
cylinder block) and oil feed pipe.
14. Oil Return Pipe Fixing Nut (4JG2-T Only)
·Remove oil return pipe fixing nut from cylinder
block.
15. Oil Cooler Hose

6A2 Ð 30 4JG2-NA/4JG2-TURBO ENGINE
13. Oil Feed Pipe: Turbo (4JG2-T Only)
·Tighten joint bolts (cylinder block and turbo
charger side) to the specified torque.
12. Water Outlet Hose: Turbo (4JG2-T Only)
·Connect to water inlet pipe of engine.
11. Water Inlet Hose: Turbo (4JG2-T Only)
·Connect to water outlet pipe.
10. Water Bypass Hose
·Water bypass hose connect to water inlet pipe.
9. Heater Hose
·Connect to heater pipe.
8. Engine Harness
·Connect five harness connecters to units on
thermostat housing.
7. Water Hose: CSD
6. A/C Compressor
·Tighten temporarily fixing bolts (upper and front
lower sides of compressor.)
·Tighten fixing bolt (rear under side of compressor)
to the specified torque by using a long extension
bar and torque wrench at under side of wheel arch.
·Tighten fixing bolts (front upper and lower sides of
compressor) to the specified torque.
5. P/S Pump Drive Belt
·Install drive belts adjust belt tension by adjusting
bolt and tighten locking bolt to the specified
torque.
·Refer to ÒDrive Belt AdjustmentÓ in section 6B.
4. Oil Level Gauge Guide Tube
·Tighten guide tube to the specified torque.
23 (23/17)N·m (kg·m/lb·ft)
37 (3.8/27)N·m (kg·m/lb·ft)
40 (4.1/30)N·m (kg·m/lb·ft)
19 (1.9/14)N·m (kg·m/lb·ft)
3. Intercooler Assembly (4JG2-T Only)
·Refer to ÒDrive Belt AdjustmentÓ in section 6B.
2. Intake Air Duct (4JG2-T Only)
1. Radiator Hose Upper
·Connect to water outlet pipe.

ENGINE MECHANICAL 6A – 29
13 Vacuum Hose
1) Disconnect vacuum hose from vacuum pump.
14. Starter Harness
1) Disconnect B terminal and put cable harness
close to chassis side.
2) Disconnect S terminal connector.
15. Engine Harness
1) Disconnect engine harness close to engine side.
16. Fuel Pipe
1) Remove fuel pipe from fuel pump and take care
not to spill fuel and let dust enter.
17. Engine Ground Cable
1) Disconnect ground cable from left rear side of
timing gear case.
18. Vacuum Hose: Vacuum Tank
Disconnect vacuum hose from vacuum pump side.
19. Glow Plug Harness
20. Transmission Assembly
1) Set transmission support tool under the
transmission.
2) Remove transmission rear mount.
3) Remove transmission fixing bolt from rear of
engine assembly except two bolts.
4) Carefully hang up engine assembly with a hoist.
5) Remove remaining two transmission fixing bolts.
6) Remove transmission assembly.
7) Remove heater hose.
8) Disconnect wire harness connector for shift on
the fly.
9) Remove vacuum hose.
21. Prepare Engine Stand
22. Engine Assembly
1) Remove engine mount fixing bolts.
2) Carefully hang up the engine assembly.
3) Take out the engine assembly making sure not
to damage the brake oil pipe and other pipe etc.
INSTALLATION
1. Engine assembly
1) Install engine in mounting position by using
hoist.
2. Transmission Assembly
1) Refer to transmission installation steps in
section 7.
3. Engine Mounting
1) After all fixing bolts (left: two bolts, rights: two
bolts) were inserted in every hole, tighten fixing
bolts to the specified torque.
Torque: 40 N·m (4 kg·m/29 lb·ft)
4. Glow Plug Harness
5. Vacuum Hose
1) Connect Vacuum Hose to Vacuum Pump
6. Engine Ground Cable
7. Fuel Pipe
1) Install fuel pipe to fuel pump.
8. Engine Harness
9. Starter Harness
10. A/C Compressor Assembly
1) Tighten temporarily the fixing bolts (upper and
front lower sides of compressor.)2) Tighten fixing bolt (rear under side of
compressor) to the specified torque.
3) Tighten fixing bolts (front upper and lower sides
of compressor) to the specified torque.
Torque: 40 N·m (4 kg·m/29 lb·ft)
Legend
(1) Tensioner
(2) Bolt
(3) Bracket
(4) A/C compressor
(5) Bolt
11. A.C Generator Harness
12. Engine Ground Cable
1) Tighten ground cable to A/C compressor
bracket.
13. Air Cleaner cover & Duct
14. Intercooler Assembly
1) Refer to “Intercooler” in this manual.
15. Radiator Assembly
1) Install rubber cushion in under left and right part
of radiator and position radiator.
2) Fix radiator with bracket.
16. Cooling Fan Assembly
1) Install cooling fan assembly and tighten fixing
bolts to the specified torque.
Torque: 8 N·m (0.8 kg·m/5.8 lb ft)
17. Fan Shroud
18. Radiator Hose
1) Connect upper and lower hose to engine side.
2) Pour coolant into radiator.
19. Install battery.
20. Connect window washer hose and install engine
hood.
1
2
3
4
5
'PS
&VSPQF
F06R200005

ENGINE MECHANICAL 6A – 35
INTAKE MANIFOLD
REMOVAL
1. Drain engine coolant and disconnect water hose
from thermostat hosing.
2. Remove intercooler assembly
Refer to “Intercooler” in this manual.
3. Remove bracket bolt of oil level gauge guide tube.
4. Remove PCV Hose.
5. Remove hoses from EGR, EGR vacuum sensor
and inlet/outlet of heater.
6. Disconnect harness connector form MAP sensor,
EGR vacuum sensor, ETC sensor, water
temperature unit, IAT sensor and EVRV.
7. Remove high pressure oil pipe.
8. Remove the two way valve.
9. Remove fuel pipe from between intake manifold
and high pressure oil pump.
10. Remove fixing bolts and nuts on the intake
manifold, then remove the intake manifold
assembly.
INSTALLATION
1. Install the intake manifold, tighten bolts and nuts to
the specified torque.
Torque : 20 N·m (2.0 kg·m/14.5 lb ft) for bolt and nut
2. Install the fuel pipe and tighten to the specified
torque.Torque :
M16 bolt (apply engine oil) 4 N·m (0.4 kg·m/2.9
lb ft)
Cap nut (M10) 13N·m (1.3 kg·m/9.4 lb ft)
Fuel pipe (M10 apply engine oil) 14 N·m (1.4
kg·m/10 lb ft)
3. Install two way valve.
Torque : 20 N·m (2.0 kg·m/14.5 lb ft)
4. Fill with about 300 cc of engine oil from the high
pressure oil pipe installation port of the oil rail using
an oil filler. If assembled without filling the oil rail
with oil, the time for starting the engine will be
longer.
5. Install the high pressure oil pipe immediately and
tighten the sleeve nut to the specified torque.
Torque : 80 N·m (8 kg·m/57.9 lb ft)
6. Reconnect harness connector to MAP sensor, EGR
vacuum sensor, ETC sensor, Water temperature
unit, IAT sensor and EVRV.
7. Connect the hoses to EGR valve, EGR vacuum
sensor, and water inlet/outlet pipe for heater.
8. Connect PCV hose.
9. Install the oil level gauge guide tube and tighten
bracket bolt.
10. Install the intercooler assembly.
Refer to “Intercooler” in this manual.
11. Connect the hose to the thermostat housing and fill
with engine coolant.
For Europe
2
1
3
3 1 42
025R200005
Legend
(1) Intake Manifold
(2) Throttle Valve Assembly
(3) EGR Valve
(4) Gasket

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 – 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.

ENGINE ELECTRICAL 6D – 23
QOS4 PREHEATING SYSTEM
GENERAL DESCRIPTION
QOS4 preheating system features a quick-on glow plug
with thermometer control of the glowing time and the
afterglow time function.
The system consists of the ECM, indicator lamp, ECT
sensor, vehicle speed sensor, relay and temperature
self-control type glow plugs.With the employment of the ECT sensor, the glow time
changes according to the engine coolant temperature,
thus allowing optimum starting conditions to be
obtained.
The after glow time function is controlled by ECM.
NOTE:
Refer to DTC P0380 and P0381 of 6E section.
SYSTEM DIAGRAM
+
-KEY
50A
ECM
50A
GLOW
50A
2
WHT/
RED
0.5
BLK/
BLU
ECM J1-15 3
WHT/
RED
3
RED/
BLKMAIN
80A
8BLK/RED
Glow
Relay
GLOW PLUG 4
BATTHeater & A/C
Relay
060RW132

6G – 6 ENGINE LUBRICATION
OIL COOLER ASSEMBLY
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 hose from water inlet and outlet
side.
2) Cloth should be put under the oil cooler to
prevent oil from flowing out.
3) Loosen fixing bolt then remove oil cooler
assembly.
Legend
(1) Oil cooler assembly
(2) Oil filter assembly
INSPECTION AND REPAIR
1. Inspect for corrosion, wear, and breaks on the oil
cooler core.
2. If a problem is found on the oil cooler core, the oil
cooler assembly must be replaced.
INSTALLATION
1. Oil cooler assembly
1) Tighten oil cooler fixing bolt to the specified
torque and install water hoses.
Torque: 29 N·m (3.0 kg·m / 21.7 lb ft)
2. Install exhaust valve assembly to turbocharger
assembly and tighten to the specified torque.
Torque: 27 N·m (2.7 kg·m / 19.5 lb ft)3. Install front exhaust pipe to the exhaust valve.
Torque:
67 N·m (6.8 kg·.m / 49.2 lb ft)
(At exhaust valve side)
43 N·m (4.4 kg·m / 32 lb ft)
(At center exhaust pipe side)
4. Install heater protector.
5. Fill engine coolant.
6. Connect battery ground cable.
7. Start engine and carefully check for leakage of oil
and coolant.
OIL COOLER SPECIFICATIONS
Cooling methodWater cooled
Multi plate type
Heat exchange Area 0.323 m
2
Heat exchange capacity >11,300 kcl/h
Relief Valve opening
245 Kpa (2.5 kg/cm2/36 psi)pressure
OIL FILTER
REMOVAL
1. Put container under the oil filter to prevent oil from
the oil filter from flowing out.
2. Use filter wrench to remove oil filter.
Filter wrench: 5-8840-0203-0
INSTALLATION
1. Apply engine oil thinly to oil filter O-ring.
2. Tighten oil filter by hand until O-ring comes in
contact with the sealing surface.
3. Use filter wrench to tighten oil filter one turn and 1/8
turn.
4. Start engine and carefully check for oil leakage from
oil filter.
SUB OIL FILTER
The sub oil filter requires no servicing until the
replacement interval is reached.
The element is designed to provide special filtering
efficiency until it becomes due for replacement.
It is recommended to check and replace the sub oil filter
when the engine is being overhauled or if it is broken
inside the engine.
For Europe1
2
050R200001