radiator cap ISUZU KB P190 2007 Workshop Owner's Guide

6B-14 ENGINE COOLING
SPECIAL SERVICE TOOL
ITEM NO. ILLUSTRATION PART NO. PART NAME


1

5-8840-0277-0

Tester; radiator cap


2

5-8840-2603-0

Adapter; radiator cap


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ISUZU KB P190 2007

Engine Cooling – V6 Engine Page 6B1–1

Section 6B1
Engine Cooling – V6
ATTENTION
Before performing any Service Operation or other procedure described in this Section, refer to 1.1 WARNING,
CAUTION and NOTES for correct workshop practices with regard to safety and/or property damage.
1 General Information ............................................................................................................ ...................3
1.1 WARNING, CAUTION and NOTES ..................................................................................................... ................... 4
1.2 Definition of WARNING, CAUTION and NOTE Statements ......................................................................... .. 4
WARNING defined ............................................................................................................................................. 4
CAUTION defined .............................................................................................................................................. 4
NOTE defined..................................................................................................................................................... 4
2 General Description ............................................................................................................ ...................5
2.1 Radiator Assembly .............................................................................................................. .................................. 5
2.2 Cooling Fan – Standard Specification.................................................................................................................. 7
Overview ................................................................................................................................................................. 7
Cooling Fan and Shroud Assembly ................................................................................................ .................... 8
Fan Motor ........................................................................................................................................................... 8
Fan Operation .................................................................................................................. .................................. 8
V6 Cooling Fan Wiring Diagram .................................................................................................. ....................... 9
Fan Assembly connector .................................................................................................................................. 10
2.3 Coolant Pump....................................................................................................................................................... 10
2.4 Coolant Outlet Housing ......................................................................................................... .............................. 11
2.5 Thermostat ........................................................................................................................................................... 11
2.6 Coolant Filler Cap ............................................................................................................. ................................... 13
2.7 Coolant Recovery Reservoir ..................................................................................................... .......................... 14
2.8 Engine Coolant Temperature Sensor .............................................................................................. ................... 15
3 Service Operations ...............................................................................................................................16
3.1 Service Notes ....................................................................................................................................................... 16
Safety .................................................................................................................................................................... 16
Periodic Servicing............................................................................................................. ................................... 16
Environmental Issues ........................................................................................................... ............................... 16
3.2 Coolant Maintenance ........................................................................................................................................... 17
Topping Up the Cooling System.................................................................................................. ....................... 18
Testing Coolant Concentration........................................................................................................................... 18
Method 1 – Refractometer................................................................................................................................ 18
Method 2 – Hydrometer.................................................................................................................................... 21
3.3 Draining and Filling Cooling System ............................................................................................ ..................... 22
Draining ................................................................................................................................................................ 22
Filling .................................................................................................................................................................... 22
3.4 Cleaning Cooling System ........................................................................................................ ............................ 25
Cooling System Reverse Flush ................................................................................................... ....................... 25
Radiator............................................................................................................................................................ 25
Engine .............................................................................................................................................................. 26
Heater Hoses and Core.......................................................................................................... .......................... 27
3.5 Drive Belt Tension ............................................................................................................................................... 28
Inspect .................................................................................................................................................................. 29
3.6 Coolant Hoses ...................................................................................................................................................... 30
3.7 Pressure Testing ............................................................................................................... ................................... 31
Coolant Filler Cap Pressure Testing ............................................................................................ ...................... 31

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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 6B1–13

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

Engine Cooling – V6 Engine Page 6B1–16

3 Service Operations
3.1 Service Notes
Safety

• To avoid serious personal injury, never
remove the coolant filler pressure cap on
the coolant outlet housing when the
engine is hot, even if the cooling system
should require filling. Sudden release of
cooling system pressure is very
dangerous.
• The vehicle is fitted with an electric
radiator cooling fan. When working around
the engine compartment, keep clear of the
fan as it may start without warning.
Before removing the coolant filler cap, allow the engine to cool, then place a shop rag over the coolant filler cap and then
slowly turn the cap anticlockwise, approximately 1½ turns, until the pressure relief position is reached. The pressure
relief position will allow any remaining pressure within the system to escape into the coolant recovery reservoir. Continue
to rotate the cap anticlockwise until the cap can be safely removed.
Periodic Servicing
The cooling system requires little attention except for maintaining the coolant to the correct level in the recovery reservoir
and periodic servicing at the time or distance intervals as outlined in 0B Lubrication and Service.
Periodic servicing includes:
1 Checking coolant level. Refer to 3.3 Draining and Filling Cooling System in this Section.
2 Checking coolant concentration. Refer to 3.2 Coolant Maintenance – Testing Coolant Concentration in this Section.
3 Pressure test cooling system and coolant filler cap. Refer to 3.7 Pressure Testing in this Section.
4 Tighten hose clamps and inspect all hoses. Refer to 3.6 Coolant Hoses in this Section. Replace hoses if swollen or deteriorated.

Always wear protective safety glasses when
working with spring type hose clamps. Failure
to do so could result in eye injury.
5 Clean out cooling system, refer to 3.4 Cleaning Cooling System – Cooling System Flush, in this Section and refill. Refer to 3.3 Draining and Filling Cooling System in this Section.
Environmental Issues
To reduce environmental impact and maintenance cost, whenever the coolant is drained from any engine, the service
records are to be checked to determine when the coolant was last changed. If more than six months life is left before the
next coolant change, then the following procedure is to be followed:
1 W hen draining the coolant from the engine, use a clean container to hold at least 12 litres of coolant and ensure that the coolant is not contaminated in the draining process.
2 After repairs have been completed, refill the engine cooling system with the drained coolant.

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ISUZU KB P190 2007

Engine Cooling – V6 Engine Page 6B1–22

3.3 Draining and Filling Cooling System
Draining

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), and then remove the coolant filler cap (located near
the brake booster assembly).

Disconnection of the battery affects certain
vehicle electronic systems. Refer to 1.1
WARNING, CAUTION and NOTES, before
removing the ground lead.
2 Disconnect the battery ground lead. Refer to 6D1– 3 Battery – V6.
3 Drain the coolant from the system via the radiator drain tap on the lower RHS of the radiator below the lower hose outlet. Attach a suitable piece of rubber tubing to the tap outlet to help direct the flow of the coolant into a suitable
container (capacity at least 12 litres).
Filling
During any service operation that requires the cooling system to be partly or completely drained, the following
instructions must be followed when refilling the cooling system, to ensure that all air is bleed from system.

• Refer to 3.1 Service Notes in this Section,
for important safety items.
• Before opening the radiator bleed screw,
the cooling system must first be
completely depressurised with the engine
coolant filler cap removed.

Do not mix different types of anti-freeze or
corrosion inhibitors, as they may be
incompatible. Always check which coolant is
to be added to the particular vehicle being
serviced. If a different type has been used in
the cooling system (or is added accidentally),
flush the system with clean water. Refer to 3.4
Cleaning Cooling System in this Section.
NOTE
Ensure that the radiator drain tap located at the
bottom of right-hand side radiator tank is closed
before proceeding.

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ISUZU KB P190 2007

Engine Cooling – V6 Engine Page 6B1–23

1 W ith the engine off, remove the coolant filler cap on
the coolant outlet housing, located at the front left-
hand side of the engine.

Figure 6B1 – 19
2 If filling a completely empty cooling system for automatic transmission models, mix 5 litres of clean
water with 5 litres of the recommended coolant or
5.2 litres of each for manual transmission models.
3 Add coolant via the engine coolant filler neck on the coolant outlet housing.
NOTE
Do not replace the coolant filler cap before
starting the engine (in step 6). Leaving the filler
cap off allows the engine to warm up without
pressurising.
4 Reconnect battery ground lead. Refer to 6D1 – 3 Battery – V6.
5 Start the engine and set the HVAC controls to: • Full hot
• Low fan
Figure 6B1 – 20
6 Run the engine at approximately 2,000 rpm to warm up the engine.
7 W ait until the radiator fan switches on.
8 W hen the radiator fan has switched on, let the engine rpm drop back to idle.
9 Turn the engine off when the radiator fan switches off.
10 Top up the coolant until full.
11 Replace the coolant filler cap.

Do not loosen or remove the radiator filler cap
when the coolant temperature is high. Steam
or boiling coolant will gush out and you may
be burnt. To open the radiator filler cap, cover
the filler cap with a thick cloth when the
coolant has cooled, release the pressure by
slowly turning the filler cap, and remove the
cap.


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ISUZU KB P190 2007

Engine Cooling – V6 Engine Page 6B1–24


12 Open the coolant reservoir tank cap.
13 Top up the radiator coolant recovery reservoir to the MAX line.
14 Reinstall the coolant recovery reservoir cap.

NOTE
This condition only applies when the cooling
system is first being filled after a major loss of
coolant. The level of coolant in the reservoir
will then drop, once the engine is started and
normal operating temperature is reached. The
coolant level should then be maintained at the
correct level (between the MAX and MIN
Lines).

Figure 6B1 – 21

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ISUZU KB P190 2007

Engine Cooling – V6 Engine Page 6B1–39

18 Check for coolant leaks. Refer to 3.7 Pressure Testing in this Section.
19 Install the radiator shroud.
20 Install the engine dress covers. Refer to 6A1 Engine Mechanical.
21 Reconnect battery ground lead. Refer to 8A_ Electrical Body & Chassis.
22 Road test the vehicle to check for correct operation.
3.9 Coolant Recovery Reservoir
Remove

Figure 6B1 – 41
Legend
1 Filler Cap
2 Reservoir

Remove the reservoir assembly attaching screws, and remove the reservoir assembly from the vehicle.
Inspect
1 Drain contents from reservoir assembly.
2 Clean the reservoir assembly with water and dry using compressed air.
3 Check reservoir and assembly for damage, for example abrasions, cracks or distortion. Replace if required.
Install
Installation of the reservoir assembly is the reverse of removal procedures, noting the following points:

1 Refill cooling recovery reservoir and cooling system with the correct concentration of coolant. Refer to 3.3 Draining and Filling Cooling System in this Section.

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