cooling ISUZU TROOPER 1995 Owner's Guide

ENGINE COOLING 68-1
SECTION 68
ENGINE COOLING
CONTENTS
General Description . . . . . . . . . . . . . . . . . . . . . . . . . . 68-1 Radiator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68-7
Diagnosis........................................ 68-3 Drive Belt Adjustment . . . . . . . . . . . . . . . . . . . . 68-1 0
On-Vehicle Service............................ 68-4 Main Data and Specifications .............. 68-12
Water Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68-4
Thermostat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68-6
Torque Specifications .................... 68-12
Special Tools ................................... 68-13
GENERAL DESCRIPTION
DOHC MODEL
Reserve tank
/ Radiator
SOHC MODEL
Radiator
Oil cooler
Throttle body
Fig. 68-1
Cylinder head
"'
RH Bank
' Cylinder bloc~~
Cylinder block
LH Bank
Cylinder block
~
lololol ~ I
~L: - -~,t
Cylinder head LH Bank d
d

68 - 2 ENGINE COOLING
The cooling system is a pressurized Engine Coolant
(EC) forced circulation type which consists of water
pump, thermostat cooling fan, radiator and other
components. The automatic transmission fluid is
cooled by the EC in radiator.
WATER PUMP
Fig. 68-2
The
EC pump is a centrifugal impeller type and is
driven by timing belt. (Fig.68-2)
THERMOSTAT
Jiggle valve
Fig. 68-3
The
thermostat is a wax pellet type with a jiggle
valve and is installed in the thermostat housing.
(Fig.68-3)
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 at
88.2
-117.6 kPa (12.8 - 17.0 psi) pressure. (No oil
cooler
provided for M!f)
Fig. 68-4
ANTI-FREEZE SOLUTION
•
•
Relation between Mixing ratio and Freezing
temperature
of the EC varies with the ratio of
anti-freeze solution in water. Proper mixing
ratio can be determined by referring to the
chart. Supplemental inhibitors or additives
claiming to increase cooling capability that have
not been specifically approved by lsuzu are not
recommended for addition to the cooling
system.
Calculation mixing ratio (Fig. 68-5)
Mixing ratio
Anti-freese
solution (Lit/gal.) =-----------------Anti-freese solution (Lit/gal.) +Water (Lit/gal.)
Note: Anti-freeze solution +Water=
Total cooling system capacity.
Lit (Us
gal)
Total Cooling
M!f 8.5 (2.24) ~-~~--------System Capacity AfT 8.8 (2.32)

Mixing ratio(%) 0 10 20 30 40 50
~
' -10
'
1
' -30

~ -40
In case of 8.5 lit total cooling system capacity
Mixing Anti-freeze
Water: solution: ratio (%) lit. (U.S. gal) lit. (U.S. gal.)
0 0 0
8.5 (2.2) 10 0.9 (0.3) 7.6 (2.0) 15
1.3 (0.4) 7.2 (1.9) 20 1.7 (0.5) 6.8 (1.8)
25 2.1 (0.6) 6.4 (1.7) 30 2.6 (0.7) 5.9 (1.6)
35 3.0 (0.8) 5.5
(1.5) 40 3.4 (0.9) 5.1 (1.3)
45 3.8 (1.0) 4.7 (1.2) 50 4.3 (1.1)
4.2 (1.1)
Fig. 68-5
ENGINE COOLING 68-3
• Mixing ratio
Check
the specific gravity of engine coolant in the
cooling system temperature ranges from oo C to
50° C using a suction type hydrometer, then deter­
mine the densityofthe Engine Coolant by referring
to the table. (Fig. 68-6)
1,100 1'-........ ........ ...... .............. Mixing ratio
~"""--r-... 1'-""' 1,1)90
........ ...... ........ ........ .......... '
1,000
'"" 1,07 o......_ 1'-........ I'-.......... I"-........ .......
I"-........ ..........
................. I"-........
'
1,080
....... I"-........ ~ ........ ......
........ "'" ~"""--r--..... 1,050
r-. ........ ~ .......... ......
---
........ ........ 1,040
r-.... !'--.. 1'-0 '"" ~"""--1'-.... ........ 1,03
1--....... ........ r--~ ........
'
1,020
....... ~ 1'-0 ~"""---.... 1,01
...... ,
'
1,000
10 20 30 40 50 60 70 Coolant temperature ("C)
Fig. 68-6
DIAGNOSIS
ENGINE COOLING TROUBLE
Condition Possible cause Correction
Engine
overheating Low Engine Coolant level Replenish
Thermo unit faulty Replace
Faulty
thermostat Replace
Faulty
Engine Coolant unit Repair or replace
Clogged
radiator Clean or replace
Faulty
radiator cap Replace
Low engine oil level or use of improper Replenish or change oil
engine oil
Clogged exhaust system Clean exhaust system or replace
faulty parts
Faulty Throttle Position sensor Replace throttle valve assembly
Open or shorted Throttle Position sensor circuit Repair or replace
Damaged cylinder head gasket Replace
Engine overcooling Faulty thermostat Replace
Engine slow to Faulty thermostat Replace
warm-up Thermo unit faulty Replace

68 - 4 ENGINE COOLING
ON-VEHICLE SERVICE
DRAINING AND REFILLING COOLING
SYSTEM
Before draining the cooling system, inspect the sys­
tem and perform any necessary service to ensure that
it is clean, does not leak and is in proper working
order. The Engine Coolant (EC) level should be be­
tween the "MIN" and "MAX" lines of reserve tank
when the engine is cold. If low, check for leakage and
add
EC up to the "MAX" line. There should not be any
excessive deposit of rust or scales around the radiator
cap
or radiator filler hole, and the EC should also be
free
from oil. Replace the EC if excessively dirty.
1. Completely drain the cooling system by opening
the drain petcock at the bottom of the radiator.
2. Remove the radiator cap.
W WARNING
To avoid the danger of being burned, do not
remove the cap while the engine and radiator
are still hot. Scalding fluid and steam can be
blown out under pressure.
3. Disconnect all hoses from the EC reserve tank.
Scrub and clean the inside of the reserve tank with
soap and water. Flush it well with clean water,
then drain it. Install the reserve tank and hoses.
WATER PUMP
3
j
2
4. Refill the cooling system with the EC using a
solution that is at least 50 percent antifreeze but no
more than 70 percent antifreeze.
5. Fill the radiator to the base of the filler neck.
Fill the EC reserve tank to "MAX" line when the
engine is cold.
6. Block the drive wheels and firmly apply the park­
ing brake.
Shift an automatic transmission to "P"
(Park) or a manual transmission to neutral.
7. Remove the radiator cap. Start the engine and
warm it up at 2,500 -3,000 rpm for about 30
minutes.
8. When the air comes out from the radiator filler
neck and the EC level has gone down, replenish
with the EC. Repeat this procedure until the EC
level does not go down. Then stop the engine and
install the radiator cap. Let the engine cool down.
9. After the engine has cooled, replenish with EC up
to the "MAX" line of the reserve tank.
10. Start the engine. With the engine running at 3,000
rpm, make sure there is no running water sound
from the heater core (behind the center console).
11. If the running water sound is heard, repeat steps 7
to 10.
Removal steps
1. Timing
belt 2. Idle pulley 3. Water pump assembly
4. Gasket
Installation steps To install, follow the removal steps in the reverse order.
Fig. 6B-7
•

EJ REMOVAL
Preparation
• Disconnect battery ground cable.
•
Drain coolant.
•
Radiator hose (on inlet pipe side)
1. Timing belt
• (Refer to Timing belt removal steps in Section
6A1, 6A2)
2. Idle pulley
3. Water pump assembly
4. Gasket
~ INSPECTION
Make necessary repair and parts replacement if ex­
treme wear or damage is found during inspection.
Should any of the following problems occur, the
entire water pump assembly must be replaced.
•
Cracks in the Engine Coolant (EC) pump body
• EC leakage from the seal unit
• Play or abnormal noise in the bearing
• Cracks or corrosion in the impeller
8 INSTALLATION
4. Gasket
• Clean the mating surface of packing before
installation.
3. Water pump assembly
• Install coolant pump assembly and tighten
bolts to the specified torque. (Fig. 68-8)
~~~ Torque N-m(lb-ft)
•
Tightening order
Fig. 68-8
18(13)
ENGINE COOLING 68-5
2. Idle pulley
• Install idle pulley and tighten bolt to the speci­
fied
torque.
~~~ Torque N-m(lb·ft) 42 (31)
1. Timing belt
• Install timing belt and adjust the belt tension.
• (Refer to Timing belt installation steps in Sec­
tion 6A1, 6A2)
• Connect radiator inlet hose and replenish EC.
• Connect battery ground cable.

68-6 ENGINE COOLING
THERMOSTAT
Removal steps
1. Inlet pipe
2. Packing
3. Thermostat
Installation steps
To
install, follow the removal steps in the reverse order.
Fig. 68-9
B REMOVAL
Preparation
• Disconnect battery ground cable.
•
Drain Engine Coolant from the radiator and
engine.
• Disconnect radiator hose from the inlet pipe.
1. Inlet pipe
2. Packing
3.
Thermostat
~ INSPECTION
Suspend the thermostat in a water-filled container
using thin wire. Place a thermometer next to the
thermostat.
Do not directly heat the thermostat.
Gradually increase the water temperature. Stir the
water so that the entire water is same temperature.
(Fig.68-10)
Confirm the temperature when the valve first
begins to open.
Valve opening temperature oc
(oF)
74.5-78.5
( 166.1 -173.3)
Confirm the temperature when the valve is fully
opened.
Valve full open temperature oc
and lift (°F)
More than 10mm
(0.39 in) at 90°C
(194°F)
Make necessary repair and parts
replacement if
extreme wear or damage is found during
inspection.
Fig.
68-10
Fig. 68-10
•

B INSTALLATION
3. Thermostat
• Install thermostat into the thermostat hous­
ing, making sure
that the jiggle valve in up
position.
2. Packing
RADIATOR
Reserve tank
6
ENGINE COOLING 68-7
1. Inlet pipe
• Connect inlet pipe and tighten bolts to the
specified torque.
I~~ Torque N·mOb·ft) 19 (14)
• Installation rubber hose
• Replenish Engine Coolant (EC)
• Start engine and check for EC leakage.
2
Removal steps
1.
Oil cooler hose 2. Radiator hose
3. Cooling fan guide; lower
4. Reserve tank hose
5. Bracket
6. Radiator assembly
Installation steps
To install, follow the removal
steps in the reverse order.
Fig. 68-11
EJ REMOVAL
Preparation
• Disconnect battery ground cable.
•
Loosen a drain plug to drain EC.
1. Oil cooler hose
• Disconnect oil cooler hose on automatic trans­
mission
(NT). (Fig.68-12)
Drain plug Cushion rubber
Fig. 68-12

'.,~-' r.
68-8 ENGINE COOLING
2. Radiator hose
• Disconnect inlet hose and outlet hose from the
engine.
3. Fan guide, lower
• Remove clips on both sides and the bottom
lock. (Fig. 68-13)
~ Cooling fan guide; lower
~
Clip
Fig. 68-13
4. Reserve tank hose
• Disconnect the hose from radiator.
5. Bracket
6. Radiator assembly
• Remove upward the radiator assembly with
hose, taking care not to damage the radiator
core
with a fan blade.
• Remove cushion rubbers on both sides at the
bottom.
~ INSPECTION
Radiator Cap
Measure the valve opening pressure of the pressuriz­
ing valve with a radiator filler cap tester. Replace the
cap
if the valve opening pressure is outside the
standard range (Fig. 68-14).
~;!v(~~i~ening pressure 88.3-117.7 (12.8-17.1)
l'i':'il Cap tester: J-24460-01
~ Adapter: J-33984-A
Check the
condition of the negative pressure valve in
the center
of the valve seat side of the cap. If consid­
erable rust
or dirt is found, or if the valve seat cannot
be
moved by hand, clean or replace the cap.
Negative
valve opening
pressure kPa (psi) 1.96-4.91 (0.28-0.71)
Fig. 68-14
Radiator Core
1. A bent fin may result in reduced ventilation and
overheating
may occur. All bent fins must be
straightened. Pay
close attention to the base of the
fin when it is being straightened.
2. Remove all dust, bugs and other foreign material.
Flushing the Radiator
Thoroughly wash the inside of the radiator and the
Engine
Coolant passages with cold water and mild
detergent. Remove all signs of scales and rust.
Cooling System Leakage Check
Use a radiator cap tester to force air into the radiator
through the filler neck at the specified pressure of 196
kPa (28.5 psi) with a cap tester:
• Leakage from the radiator
• Leakage from the coolant pump
• Leakage from the water hoses
• Check the rubber hoses for swelling.
rt:\1 Cap tester: J-24460-01
~ Adapter: J-33984-A
Fig. 68-15
•

E!) INSTALLATION
6. Radiator assembly
• Install cushion rubbers on both sides of radia­
tor bottom.
• Install radiator assembly with hose, taking
care
not to damage the radiator core with a fan
blade.
5. Bracket
• Support the radiator uppertankwith the bracket
and secure the radiator.
4. Reserve tank hose
3. Fan guide, lower
2. Radiator hose
• Connect inlet hose and outlet hose to the
engine.
1. Oil cooler hose (A/T)
• Connect oil cooler hose for automatic trans-
mission.
• Connect battery ground cable.
• Pour engine coolant.
• Pour engine coolant up to filler neck of radia­
tor, and up to MAX mark of reserve tank. (Fig.
68-16)
Reserve tank
Fig. 68-16
ENGINE COOLING 68-9
U7 Important operation (in case of 100% Engine
V Coolant change) procedure for filling with
Engine Coolant
• Fill
with Engine Coolant (EC) to the radiator
filler neck.
• Fill with EC to the "MAX" line on the reservoir.
• Start the engine with the radiator cap removed
and bring
to operating temperature by running
engine at
2,500-3,000 revolution per minute
for 30 minutes.
• By EC temperature gauge reading make sure
that the thermostat is open.
• If air bubbles come up to the radiator filler
neck, replenish with EC repeat until the EC
level does not drop any further. Install the
radiator cap and stop the engine.
• Replenish EC to the "MAX" line on the reser­
voir and leave as it is until the engine gets cool.
• After the engine gets cool, start the engine and
make sure there is no
water running noise
heard
from the heater core while the engine
runs
at 3000 revolution per minute.
• Should water running noise be heard, repeat
the same procedure from the beginning.

68 -10 ENGINE COOLING
DRIVE BELT ADJUSTMENT
Power steering oil pump
Lock bolt
Bolt position
Adjuster
Crank
pulley
Crank; AC. Generator cooling fan
Crank;
Air Conditioning compressor
Crank; Power steering
oil pump
Air Conditioning compressor
Lock bolt Crank pulley
Fig. 68-17
(b!] INSPECTION
Check drive belts for wear or damage, and replace
with new ones as necessary. Check belts for tension,
and
adjust as necessary.
WCAUTION:
• Unlike the conventional V-type belt, auto ten­
sion
belt must use a belt tension gauge, if
possible, for its tension adjustment because
feel based adjustment may not lead to accu­
rate
belt tension.
Tension
readjustment of auto tension belt
should be made only once when V-type HM'
tension has dropped to 40 lb or less and polyV­
type's to 50 lb or less after the vehicle's total
running mileage of 621 miles.
As for air conditioning (A/C) compressor driv­
ing belt, it is difficult to use a belt tension
gauge.
Depress
belt with 98N (221b) and make sure
that slackness is in the range of0.315-0.472 in.
AC. Generator and cooling fan drive belt
Air Conditioning compressor drive belt
Fig. 68-18
Belt tension range to be targeted for cold setting.
Using a
Borrough drive belt tension gauge.
(I b)
Kind of Initial Tension at belt tension readjustment
AC generator & fan Poly V type 180 110 pulley drive belt ±10
±10
A/C compressor Poly V type 120
100
drive belt ±20
±20
Power steering
V-type HM 90 ±20 pump drive belt
•