2007 ISUZU KB P190 cooling

Engine Cooling – V6 Engine Page 6B1–31

3.7 Pressure Testing
Coolant Filler Cap Pressure Testing

Refer to 3.1 Service Notes in this Section, for
important safety items.




1 Allow engine to cool to ambient temperature (less than 50 ° C), then remove coolant filler cap.
2 Inspect and clean both sides (1) of coolant filler cap gasket with a wet cloth.
NOTE
Use only water to wet the cleaning cloth.
Figure 6B1 – 28
3 Lift centre vacuum valve. Clean and inspect the gasket and sealing surface under the valve (1).
Figure 6B1 – 29

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Engine Cooling – V6 Engine Page 6B1–32

4 Attach coolant filler cap (2) to a commercially
available cooling system pressure tester (1), using
the pressure cap adaptor.
5 Slowly pressurise cap to 120 – 130 kPa. The cap is serviceable if it unloads slightly above this pressure
range and holds pressure at 120 kPa.
NOTE
Should the cap fail to reach or hold the
specified pressure, replace the cap.

Figure 6B1 – 30
6 Prior to installing coolant filler cap ensure that the coolant filler neck cap seating surface is clean and
free from obstruction.
Figure 6B1 – 31
Cooling System Pressure Testing

Refer to 3.1 Service Notes in this Section, for
important safety items.
1 Allow the engine to cool to ambient temperature (less than 50 ° C), then remove coolant filler cap.
2 Ensure that the coolant level is correct.

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Engine Cooling – V6 Engine Page 6B1–33

3 Install the coolant filler neck adaptor, to a
commercially available cooling system pressure tester
(1).
4 Install the assembly to the engine coolant filler neck.
5 Using compressed air, blow dry any spilled coolant around coolant filler neck.

Do not exceed the stated pressure, as
damage to the cooling system could
otherwise result.
6 Using the cooling system pressure tester pump, pressurise cooling system to 130 kPa absolute
maximum and check for leaks at the following points:
• All hoses and hose connections
• Overflow hose connection at coolant outlet
housing connection

Figure 6B1 –
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32
• Radiator seams and core
• Corroded or faulty engine W elch plugs
• Coolant pump and gasket
• Thermostat housing and coolant inlet pipe connection
• Radiator drain tap and bleed screw
• Vehicle heating system (e.g. heater core and water valve)
NOTE
For heater Removal and Installation, refer to 2A –
Heater and Air-conditioning.
7 Check engine oil dipstick for evidence of engine oil contamination with coolant.
8 If pressure will not hold, there is a leak in the cooling system. Repair as necessary.
NOTE
If visible loss of coolant is not evident from
pressure testing, then the use of a dye and black
light, may be necessary. Refer to 4.7 Black
Light and Dye Leak Diagnosis Method, in this
Section.

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Engine Cooling – V6 Engine Page 6B1–34

3.8 Thermostat
Remove

Do not remove coolant filler cap while the
engine coolant temperature is above 50 °
°°
°
C, as
personal injury may result.
1 Allow engine to cool to ambient temperature (less than 50 ° C), then remove the coolant filler cap (located at the
front left-hand side of the engine).

Disconnection of the battery affects certain
vehicle electronic systems. Refer to 00
Warnings, Cautions and Notes, before
removing the ground lead.
2 Disconnect the battery ground lead. Refer to 6D1-3 Battery – V6.


Refer to ‘
‘‘
‘
Environmental Issues ’
’’
’
in 3.1
Service Notes, before draining the coolant.
3 Drain the coolant from the system. Refer to 3.3 Draining and Filling Cooling System in this Section.
4 Remove the complete intake manifold assembly. Refer to 6A1 Engine Mechanical – V6.
5 Plug each of the exposed intake ports with lint free cloth to prevent the entry of foreign matter.
6 Remove the coolant inlet pipe. Refer to 3.12 Coolant Inlet Pipe in this Section.


Always wear protective safety glasses when
working with spring type hose clamps.
Failure to do so could result in eye injury.
7 Use a straight-blade screwdriver (3) to release the heater hose quick connect clips (4).
8 Disconnect the heater hoses (1) from the heater pipes (2) in two places.
Figure 6B1 –
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–
33

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Engine Cooling – V6 Engine Page 6B1–35

9 To gain easier access to the heater pipe flange and
thermostat housing bolts, disconnect the engine
harness and lay back on the right side of the engine
bay. Apart from those harness connectors removed
during the intake manifold removal, this involves the
removal of wiring harness connectors and fasteners,
as detailed:
a Pull out the release bar (arrows) on each of the ignition coil packs (1) on cylinders 2, 4 and 6,
before disconnecting each connector.
b The coolant temperature sensor.
c The left side Pre-O2 sensor connector, 2, 4 & 6.
NOTE
Refer to 8A – Electrical Body & Chassis for the
location of harness connectors, not shown.

Figure 6B1 –
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–
34
10 Remove the bolt (1) securing the engine harness ground terminal (2), to the cylinder block.
11 Prise both locking legs of the left side engine harness former (4), free, then lift up on the harness former to
release.

Figure 6B1 –
––
–
35
12 W orking at the rear of the engine, disconnect the engine harness to transmission harness connector (1),
as required.
13 Remove the two bolts (2) securing the engine harness former (3) to the rear of the engine.
14 Carefully lift the engine harness free and drape on the right side of the engine.


NOTE
For further information on removing the
thermostat housing and associated components,
refer to 6A1 Engine Mechanical – V6.
Figure 6B1 –
––
–
36

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Engine Cooling – V6 Engine Page 6B1–36

15 Remove the heater pipe assembly (1) to right-hand
side cylinder head (2) attaching bolt (3).
16 Remove the heater pipe assembly to thermostat housing (4) attaching bolts (5), then remove the heater
pipe assembly.
17 Remove and discard the heater pipe assembly to thermostat housing O-ring seals (6).

Figure 6B1 –
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–
37
18 Remove the three thermostat housing attaching bolts (1), rubber grommets (2), then remove the thermostat
housing (3).
NOTE
The upper thermostat housing attaching bolt is
longer than the two lower bolts.
19 Remove and discard the thermostat housing to engine block gasket (4).

Figure 6B1 –
––
–
38

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Engine Cooling – V6 Engine Page 6B1–37

Test
1 W ith the thermostat (1) installed in the housing,
suspend it and a suitable thermometer (2) in a
container of 50% clean fresh water and 50% Dexron ®
long life coolant, (conforming to GM 6277M).
NOTE
Neither the thermostat assembly (1) nor the
thermometer (2) should rest on the bottom of the
container because of uneven concentration of
heat at this point when the container is heated.
2 Heat container until thermostat begins to open. Agitate solution to ensure uniform temperature. Note
temperature and ensure thermostat opens within
specified temperature range.
Thermostat Opening Specifications
Opening Temperature ........................................ 82 ° C
Fully Open Temperature .................................... 95 ° C
3 Replace thermostat if it does not meet these operating
conditions.
Figure 6B1 –
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–
39
Dismantle

Only dismantle the thermostat if a reverse
flushing operation of the cylinder block is to
be carried out. If the testing operation
indicates that the thermostat is faulty, then
the housing and thermostat are only serviced
as an assembly.
Remove thermostat (1) from thermostat housing (2) as
follows:
a Secure the thermostat housing by gripping in a vice fitted with soft jaws.

Always wear protective safety glasses when
working with spring-loaded devices. Failure
to do so could result in eye injury.
b Depress the retaining bar (3) on both sides of the thermostat and rotate the thermostat until it
clears the retaining lugs (4) on the thermostat
housing (2).
c Release the thermostat spring force.
d Remove the thermostat assembly from the thermostat housing.
Figure 6B1 – 40
Reassembly
The reassembly process is the reverse to that used for disassembly, with the following exceptions:
1 Check that the valve sealing surface is undamaged.
2 W ipe the valve sealing surface to ensure a clean surface.

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Engine Cooling – V6 Engine Page 6B1–38

Install

Always wear protective safety glasses when
working with spring-loaded devices. Failure to
do so could result in eye injury.
1 Install the thermostat into the housing (reverse to removal procedure).
2 Ensure that the engine block and thermostat housing mating surfaces are clean and dry.
3 Install a new gasket to the thermostat housing.
4 Install the thermostat housing to the engine block and secure with the attaching bolts (with rubber grommets installed). Tighten all bolts to the correct torque specification.
Thermostat housing to engine
block bolt torque specification ..............................10 N.m
5 Ensure that the heater pipe assembly and thermostat housing mating surfaces are clean and dry.
6 Install new O-rings to the heater pipe assembly.
7 Install heater pipe assembly to thermostat housing and secure with the attaching bolts. Tighten all bolts to the correct torque specification.
Heater pipe assembly to thermostat
housing bolt torque specification ..........................10 N.m
8 Install heater pipe assembly to right-hand cylinder head bolt. Tighten bolt to the correct torque specification. Heater pipe assembly to cylinder
head bolt torque specification ..............................35 N.m

Always wear protective safety glasses when
working with spring type hose clamps. Failure
to do so could result in eye injury.
9 Reinstall the engine wiring harness, securing the rear harness former to the rear of the engine with the two retaining bolts, tightened to the correct torque specification.
Rear engine harness former
retaining bolts torque specification .......................15 N.m
10 Reinstall the left side engine harness former to the two locating pegs, then push inward to secure.
11 Reinstall the bolt securing the engine harness ground terminal, to the left side of the cylinder block and tighten to the correct torque specification.
Engine harness ground terminal
attaching bolt torque specification ........................12 N.m
12 Reinstall each wiring harness connector to its correct location, ensuring that all security clips are installed correctly.
13 Connect the heater hoses to the heater pipe assembly.
14 Install the coolant inlet pipe. Refer to 3.12 Coolant Inlet Pipe in this Section.
15 Close the radiator drain tap on the lower LHS of the radiator and remove the piece of rubber tubing to the tap outlet.
16 Reinstall the complete intake manifold assembly. Refer to 6A1 Engine Mechanical.
17 Refill cooling system. Refer to 3.3 Draining and Filling Cooling System in this Section.

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