2007 ISUZU KB P190 coolant

Engine Cooling – V6 Engine Page 6B1–2

Cooling System Pressure Testing ................................................................................................ ...................... 32
3.8 Thermostat ........................................................................................................................................................... 34
Remove ................................................................................................................................................................. 34
Test ....................................................................................................................................................................... 37
Dismantle ...................................................................................................................... ........................................ 37
Reassembly .......................................................................................................................................................... 37
Install .................................................................................................................................................................... 38
3.9 Coolant Recovery Reservoir ..................................................................................................... .......................... 39
Remove ................................................................................................................................................................. 39
Inspect .................................................................................................................................................................. 39
Install .................................................................................................................................................................... 39
3.10 Coolant Pump................................................................................................................... .................................... 40
Remove ................................................................................................................................................................. 40
Inspect .................................................................................................................................................................. 43
Reinstall ................................................................................................................................................................ 43
3.11 Coolant Outlet Housing ......................................................................................................... .............................. 45
Remove ................................................................................................................................................................. 45
Reinstall ................................................................................................................................................................ 46
3.12 Coolant Inlet Pipe............................................................................................................. .................................... 46
Remove ................................................................................................................................................................. 46
Install .................................................................................................................................................................... 48
3.13 Cooling Fan and Shroud Assembly ................................................................................................ ................... 48
Remove ................................................................................................................................................................. 48
Install .................................................................................................................................................................... 50
Disassemble ......................................................................................................................................................... 51
Reassemble .......................................................................................................................................................... 51
3.14 Flexible Transmission Cooler Hose .............................................................................................. ..................... 51
Replace ................................................................................................................................................................. 51
Reinstall ................................................................................................................................................................ 53
3.15 Radiator ....................................................................................................................... ......................................... 54
Remove ......................................................................................................................... ........................................ 54
Reinstall ................................................................................................................................................................ 56
Radiator Repair Procedure...................................................................................................... ............................ 57
Repairable Leaks ............................................................................................................................................. 57
Repair Method.................................................................................................................................................. 58
Tube Blocking................................................................................................................................................... 58
Header Repair .................................................................................................................. ................................ 58
General Core Repair ............................................................................................................ ............................ 59
Transmission Oil Cooler Leak Test .............................................................................................. .................... 60
Transmission Oil Cooler Seal Replacement. ...................................................................................... .............. 60
4 Engine Cooling System Diagnosis .....................................................................................................61
4.1 Poor Heater Operation......................................................................................................................................... 61
4.2 Leaking Cylinder Head Gasket ................................................................................................... ........................ 61
4.3 Question the Customer ....................................................................................................................................... 61
4.4 Diagnostic Chart .................................................................................................................................................. 61
4.5 Problems Not Requiring Disassembly of Cooling System ........................................................................... .... 63
4.6 Problems Requiring Disassembly of Cooling System ...................................................................................... 63
4.7 Black Light and Dye Leak Diagnosis Method .................................................................................................... 63
5 Specifications .......................................................................................................................................64
6 Torque Wrench Specifications................................................................................................... .........66
7 Special Tools ........................................................................................................................................67

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ISUZU KB P190 2007

Engine Cooling – V6 Engine Page 6B1–3

1 General Information
The cooling system for the HFV6 engine has been re-designed to accommodate this engine’s unique configuration and
engine cooling performance requirements. The following list is a summary of new and modified components:
• Revised radiator assembly.
• New plumbing including radiator hoses, inlet pipe, heater pipes, heater hoses and heater water valve.
• New rear mount thermostat assembly and thermostat housing.
• New coolant outlet with pressure cap.
• New coolant specification.
• New side chutes and radiator shroud.
• Modified cooling fan operating strategy.
• A four stage cooling fan operating system is used.
The cooling fan motor is controlled by duty signal from the ECM which results in the fan operating from low speed Stage
1), up to high speed (Stage 4).
Operation of the cooling fan is dependant on the engine temperature, vehicle speed, A/C request (where fitted) and A/C
system pressure. Refer to 6C1 – 1 Engine management general information.


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ISUZU KB P190 2007

Engine Cooling – V6 Engine Page 6B1–4

1.1 WARNING, CAUTION and NOTES
This Section contains various W ARNINGS, CAUTIONS and NOTE statements that you must observe carefully to reduce
the risk of death or injury during service, repair procedures or vehicle operation. Incorrect service or repair procedures
may damage the vehicle or cause operational faults. W ARNINGS, CAUTION and NOTE statements are not exhaustive.
HOLDEN LTD can not possibly warn of all the potentially hazardous consequences of failure to follow these instructions.
1.2 Definition of WARNING, CAUTION and NOTE Statements

Diagnosis and repair procedures in this Section contain both general and specific W ARNING, CAUTION and NOTE
statements. HOLDEN LTD is dedicated to the presentation of service information that helps the technician to diagnose
and repair the systems necessary for proper operation of the vehicle. Certain procedures may present a hazard to the
technician if they are not followed in the recommended manner. W ARNING, CAUTION and NOTE statements are
designed to help prevent these hazards from occurring, but not all hazards can be foreseen.
WARNING defined
A W ARNING statement immediately precedes an operating procedure or maintenance practice which, if not correctly
followed, could result in death or injury. A W ARNING statement alerts you to take necessary action or not to take a
prohibited action. If a W ARNING statement is ignored, the following consequences may occur:
• Death or injury to the technician or other personnel working on the vehicle,
• Death or injury to other people in or near the workplace area, and / or
• Death or injury to the driver / or passenger(s) of the vehicle or other people, if the vehicle has been improperly
repaired.
CAUTION defined
A CAUTION statement immediately precedes an operating procedure or maintenance practice which, if not correctly
followed, could result in damage to or destruction of equipment, or corruption of data. If a CAUTION statement is ignored,
the following consequences may occur:
• Damage to the vehicle,
• Unnecessary vehicle repairs or component replacement,
• Faulty operation or performance of any system or component being repaired,
• Damage to any system or components which depend on the proper operation of the system or component being
repaired,
• Faulty operation or performance of any systems or components which depend on the proper operation or
performance of the system or component under repair,
• Damage to fasteners, basic tools or special tools and / or
• Leakage of coolant, lubricant or other vital fluids.
NOTE defined
A NOTE statement immediately precedes or follows an operating procedure, maintenance practice or condition that
requires highlighting. A NOTE statement also emphasises necessary characteristics of a diagnostic or repair procedure.
A NOTE statement is designed to:
• Clarify a procedure,
• Present additional information for accomplishing a procedure,
• Give insight into the reasons for performing a procedure in the recommended manner, and / or
Present information that gives the technician the benefit of past experience in accomplishing a procedure with greater
ease.

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ISUZU KB P190 2007

Engine Cooling – V6 Engine Page 6B1–10

Fan Assembly connector

Figure 6B1 – 5

2.3 Coolant Pump
The coolant pump is a centrifugal vane impeller type pump. The pump consists of a housing and an impeller. The
impeller is a flat plate mounted on the pump shaft with a series of flat or curved blades (vanes). W hen the impeller
rotates, the coolant between the vanes is thrown outward by centrifugal force. The impeller shaft is supported by sealed
bearings. The sealed bearings do not need to be lubricated. Grease cannot leak out, dirt and water cannot get in as long
as the seal is not damaged or worn.
The coolant pump (1) is mounted to the engine front cover
and is driven by the crankshaft pulley (2) via a multi-ribbed
drive belt (3), turning the pump pulley (4), bolted to the
coolant pump flange (5). Coolant enters the engine
through the coolant inlet pipe and thermostat at the rear of
engine and passes through the engine to the coolant
pump on the front engine cover and exits via the coolant
outlet housing (6) located at the front of the intake
manifold.

Figure 6B1 – 6

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ISUZU KB P190 2007

Engine Cooling – V6 Engine Page 6B1–11

2.4 Coolant Outlet Housing
The coolant outlet housing (1) is located at the front of the
intake manifold (2).


Figure 6B1 – 7
2.5 Thermostat
The thermostat housing (1) is located at the rear of the
engine between the coolant inlet pipe (2) and the rear of
the intake manifold, underneath the heater pipe assembly
(3).


Figure 6B1 – 8

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ISUZU KB P190 2007

Engine Cooling – V6 Engine Page 6B1–12


Figure 6B1 – 9
Legend
1 Bypass Valve
2 Thermostat Retaining Bar
3 Thermostat Assembly Retaining Lugs
4 Wax Pellet 5 Air Bleed Valve
6 Piston Centre Support
7 Thermostat Housing
8 Piston 9 Rubber Diaphragm
10 Thermostat Spring
11 Bypass Spring

A wax pellet type thermostat is used in the coolant inlet passage to control the flow of coolant, providing fast engine
warm up and regulating coolant temperature. The wax pellet or power element in the thermostat expands when heated
and contracts when cooled. The wax pellet is connected through a piston to a valve and when the pellet is heated,
pressure is exerted against a metal valve, which is forced to open.
As the pellet is cooled, the contraction allows a spring to close the valve. Thus, the valve remains closed while the
coolant is cold, preventing circulation of coolant through the radiator, but allowing the coolant to circulate throughout the
engine to warm it quickly and evenly. As the engine becomes warm, the pellet expands and the thermostat opens,
permitting the coolant to flow through to the radiator where heat is transferred to the surrounding air, through the radiator
walls.
This opening and closing of the thermostat valve permits enough coolant to enter the radiator to keep the engine within
specified temperature limits.
The thermostat also provides a restriction in the cooling system, even after it has opened. This restriction creates a
pressure difference, which prevents cavitation at the coolant pump and forces coolant to circulate through the engine
block.

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ISUZU KB P190 2007

Engine Cooling – V6 Engine Page 6B1–13

2.6 Coolant Filler Cap
Figure 6B1 – 10 Figure 6B1 – 11

The pressurised coolant filler cap (1), fitted to the filler neck (2) on the coolant outlet housing, causes the cooling system
to operate at higher than atmospheric pressure. The higher pressure raises the boiling point of the coolant, resulting in
increased engine cooling efficiency. The coolant filler cap contains a pressure valve (3) and a vacuum (atmospheric)
valve (4).
Referring to view ‘A’, the pressure valve is held against its seat by a spring (5), which determines the maximum operating
pressure of the cooling system (120 kPa ).
Referring to view ‘B’, the vacuum valve (4) is held against its seat by a light spring and opens during cool down because
of the drop in pressure with contraction of the coolant volume. This pressure drop over-comes the spring force and the
vacuum valve is opened, preventing the radiator hoses from collapsing. In addition, coolant can also flow back into the
cooling system from the coolant recovery reservoir while this valve is open maintaining a full volume of coolant within the
engine and radiator.

Should the radiator pressure cap require
replacement, only fit the correct cap (with the
correct pressure-rating) for this engine. Refer
to the current release of Partfinder™ for this
information.

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ISUZU KB P190 2007

Engine Cooling – V6 Engine Page 6B1–14

2.7 Coolant Recovery Reservoir
The coolant is maintained at the ideal level in the radiator by the coolant filler cap and the coolant recovery reservoir,
resulting in increased cooling efficiency.
The coolant recovery reservoir is located on the left-hand side front of the engine compartment, between the radiator
support panel and air cleaner assembly. The coolant recovery reservoir is connected to the radiator overflow connection
by a small diameter hose.
As the engine temperature rises, the coolant is heated and expands. The fluid displaced by expansion flows from the
radiator into the recovery reservoir.
W hen the engine is turned OFF, the coolant contracts as it cools. Coolant is then drawn back into the radiator through
the coolant filler cap atmospheric valve.
Coolant level should be maintained between the MAX and
MIN indicator lines on the coolant recovery reservoir, as
shown in Figure 6B1 – 12, when the engine is cold.
The cooling system is designed to use a coolant, DEX-
COOL® long-life coolant or equivalent to GM specification
6277M (a mixture of ethylene glycol antifreeze and
corrosion inhibitors and water), rather than plain water to
maintain the integrity of the cooling system, and to prevent
oxidation occurring within the engine.
NOTE
Some HFV6 Series vehicle markets call for
DEX-COOL® long-life coolant and others for
its equivalent, known as Extended Life Anti-
freeze Coolant, conforming to GM specification
6277M. If in doubt regarding the correct
coolant to be used, refer to the Owner’s
Handbook.


Figure 6B1 – 12

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ISUZU KB P190 2007