2007 ISUZU KB P190 cooling

Engine Cooling – V6 Engine Page 6B1–55


Figure 6B1 – 63
Legend
1 Radiator Hose – Upper
2 Radiator Hose – Lower
3 Hose Clamp – Upper Hose to Engine Outlet Housing 4 Hose Clamp – Upper Hose to Radiator Inlet
5 Hose Clamp – Lower Hose to Radiator Outlet
6 Hose Clamp – Lower Hose to Engine Coolant Inlet Pipe

6 Remove radiator upper hose (1) from radiator connection.
7 Remove radiator lower hose (2) from radiator connection.
8 Remove the two rubber insert mounting brackets supporting the top of the radiator.
9 Remove the two lower attaching bolts (either side) and the rubber mounts.
10 Remove the radiator from the vehicle.

Always wear protective safety glasses when
working with spring type hose clamps. Failure
to do so could result in eye injury.




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ISUZU KB P190 2007

Engine Cooling – V6 Engine Page 6B1–56

Reinstall
Installation of the radiator is the reverse of removal procedures, noting the following points:
1 Before installing radiator, inspect core to ensure that there is no foreign matter in core fins. Clean out between core fins with compressed air, blowing from rear to front.
2 If the vehicle is fitted with an automatic transmission, remove plugs from the removed cooling pipe ends and the two quick connect fittings.
3 After wiping cooler line ends and smearing clean automatic transmission fluid over each flared line end, push into the quick connect fitting to engage. As a security check, tug on each line to ensure correct engagement.
4 Check the transmission fluid level. Refer to the following references as required:
• 7C4 Automatic Transmission
• 4L60E On-vehicle Servicing
5 Install the following hoses:
a. Lower radiator hose, securing with the hose clamp.
b. Upper radiator hose, securing with the hose clamp.
6 Install the radiator cooling fan and shroud assembly. Refer to 3.13Cooling Fan and Shroud Assembly in this Section. Ensure that electrical connectors and the transmission cooler lines are seated correctly in the integral
retainer clips before install upper radiator shroud.
7 Refill cooling system. Refer to 3.3 Draining and Filling Cooling System in this Section.
8 Check for coolant leaks. Refer to 3.7 Pressure Testing in this Section.
9 Reconnect battery ground lead. Refer to 8A Electrical Body & Chassis.
10 Check cooling fan operation. Refer to 6C1-2 Engine Management Diagnostics. Also check for correct rotational direction of cooling fan.

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ISUZU KB P190 2007

Engine Cooling – V6 Engine Page 6B1–57

Radiator Repair Procedure
Repairable Leaks

Figure 6B1 – 64
Legend:
1 Left-hand Side Tank Seal
2 Core Tubes
3 Right-hand Side Tank Seal 4 Oil Cooler Pipe Fittings
5 Joint Between Tube and Header
There are two types of leaks that can be repaired on the aluminium-plastic radiator; core leaks and automatic
transmission oil cooler seal leaks. Leaks in the plastic tanks or the seals between the side tanks and the headers cannot
be repaired; therefore the radiator must be replaced.
Core leaks may occur in a tube or in the joints between the tubes and the headers. Seal leaks may occur in the joints
between the plastic tanks and the headers or in the joints between the oil cooler fittings and the tank (vehicles with
automatic transmission).
W hile some leaks can be repaired while the radiator is installed in the vehicle, it is strongly recommended that the
radiator is first removed from the vehicle.
NOTE
Minor damage to tubes, or tube to header joint
(holes up to 1 mm diameter max.) can be
repaired. Core replacement is necessary if
damage is any greater.

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Engine Cooling – V6 Engine Page 6B1–58

Repair Method
Repairs to the aluminium radiator core should only be made using the recommended 'Aluminised Silicon' based liquid
repair agent, in accordance with the recommended procedure outlined in General Core Repair in this Section. Refer to
the current Partfinder™ for Aluminised Silicon base liquid part number.
For damaged areas that are between the cooling fins, it
may be necessary to remove some of the fins. Do not
remove more fins than is necessary. Usually 6 mm
(distance ‘A’) beyond the leak or damage area, up to a
maximum of 25 mm of total fin material, is enough to
make an effective repair.


Figure 6B1 – 65
Tube Blocking
If a tube is severely damaged, it can be blocked off.
NOTE
Do not block off more than two tubes in a
radiator. Blocking off more than two tubes will
reduce the cooling capacity and efficiency of
the system and possibly result in an
overheated engine.
The tube should be cut off 6 mm from the header (1) and
pinched shut before it is cleaned and sealed. Refer to
General Core Repair in this Section.

Figure 6B1 – 66
Header Repair
If the header or a tube near the header requires a repair, the side tank does not have to be removed. If the repair
requires the removal of the header tank, then the radiator must be replaced.

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ISUZU KB P190 2007

Engine Cooling – V6 Engine Page 6B1–59

General Core Repair
NOTE
The need for careful preparation of the surface in
the repair area cannot be over-emphasised. If the
leak area surface is not clean, the repair material
will not adhere to the surface.

Refer to ‘
‘‘
‘
Environmental Issues ’
’’
’
in 3.1
Service Notes, before draining the coolant.
1 Drain the coolant from the system. Refer to 3.3 Draining and Filling Cooling System in this Section.
2 Remove the radiator. Refer to 3.15 Radiator in this Section.
3 If necessary, carefully cut away fins to expose the damaged area.
NOTE
Do not cut away more than 25 mm total fin
material.
4 Clean away dirt etc. with water. Dry the affected area using hot air from a hair drier.

Do not apply flame to dry damaged area.
5 Clean affected area with petrol to remove any traces of oil.
6 Thoroughly stir contents of repair agent.
NOTE
In cases of extended shelf life, the silicon in
solution may separate from the thinner base.
Should this occur, mix contents well until agent is
again homogeneous.
7 Apply repair agent sparingly to damaged area. Do not apply an excessive amount, as this will cause blockage of the radiator tube.
NOTE
Use a clean, dry wooden applicator to 'DRIP'
agent onto damaged area of radiator.
8 Allow radiator to stand in a clean, dry area for a minimum of 3 hours (at ambient temperature of 20 – 30 ° C) with
adequate ventilation.
NOTE
Do not apply heat or flame to promote drying.
9 Reinstall the radiator. Refer to 3.15 Radiator in this Section.

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Engine Cooling – V6 Engine Page 6B1–60

Transmission Oil Cooler Leak Test
If the transmission oil cooler is suspected of leaking oil, test it before the radiator is replaced, as follows:
1 Disconnect oil cooler pipes at the flexible hose connections. Refer to 3.14 Flexible Transmission Cooler Hose, in this Section.
2 Plug one of the connections, using a blocked pipe fitting and attach an air supply to the other flexible hose.
3 Remove coolant filler cap and check that the coolant is filled to the coolant filler cap filler neck.
4 Apply air pressure gradually, increasing up to an absolute maximum of 110 kPa. If bubbles appear in radiator neck, the oil cooler is leaking and the radiator assembly must be replaced.
Transmission Oil Cooler Seal Replacement.
It is strongly recommended that the transmission oil cooler connector fittings to the right-hand side radiator header tank,
not be disturbed. If coolant is found to leak from either of these two areas, then the radiator should be replaced.


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ISUZU KB P190 2007

Engine Cooling – V6 Engine Page 6B1–61

4 Engine Cooling System
Diagnosis
4.1 Poor Heater Operation
Little or no heat coming from the heater, especially at idle could be an indication of a cooling system problem.
As the coolant level begins to get lower than normal, air enters the system to replace the missing coolant. The heater
core is one of the highest parts of the cooling system and therefore, the first area to lose coolant circulation.
At first, with a small amount of coolant loss, lack of heat will be most noticeable at idle. As driving speed increases, the
engine pumps more coolant and more heat is now able to pass through the heater core.
If coolant level drops even lower, heater operation will become less effective, even during normal driving. Cooling and
engine systems can be adversely affected if problem is not corrected before overheating occurs.
4.2 Leaking Cylinder Head Gasket
Combustion gases leaking past the cylinder head gasket can pressurise the cooling system, forcing coolant out of the
system and into the coolant recovery reservoir.
Indications are air bubbles in the coolant or an overflow condition of the recovery reservoir.
4.3 Question the Customer
To avoid needless time and cost in diagnosing cooling system complaints, the customer should be questioned about
driving conditions that place abnormal loads on the cooling system.
1 Is overheating occurring after prolonged idle, in gear, with air conditioning system operating?
If answer is YES – instruct owner on driving techniques that would avoid overheating such as:
• Idle in neutral as much as possible – increase engine rpm to get higher air flow (due to an increase in voltage
to the fan) and coolant flow through the radiator
• Turn air conditioning system off during extended idling periods if overheating is indicated on temperature
gauge. Further diagnostic checks should not be required
2 Is overheating occurring after prolonged driving in slow city traffic, traffic jams, parades, etc?
If answer is YES, explain driving technique to the customer, that would avoid overheating – same as for prolonged idle – No.1. Further diagnostic checks should not be required.
4.4 Diagnostic Chart
If none of the above conditions apply, refer to the following Diagnosis Chart.
To effectively use this chart, question the customer to determine which of the following three categories apply to the
complaint:
1 If complaint is hot indication on temperature gauge.
W as temperature reading accompanied by boiling?
• If answer is YES, go to overheating on diagnosis chart
• If answer is NO, check temperature gauge and sender
2 If complaint is boiling – go to overheating on diagnosis chart.
3 If complaint is coolant loss. Determine if customer is filling the system correctly.
4 If incorrect filling is not the problem, go to coolant loss in the diagnosis chart.

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ISUZU KB P190 2007

Engine Cooling – V6 Engine Page 6B1–62


Refer to 3.1 Service Notes in this Section, for
important safety items before removing the
coolant filler pressure cap or servicing the
system.

The cooling system is designed to operate at
120 –
––
–
130 kPa and a maximum temperature
not above 130 °
°°
°
C.
Cooling System Diagnosis
Step Action Result Yes No
1
Check Temperature gauge reading High Temp.
Low Temp. Go to Step 2
Go to Step 6 –
2
Check drive belt condition and tension. Refer to 6A1
Engine Mechanical. To Specification Go to Step 3 Replace drive
belt or
tensioner.
3 Check coolant Boiling Go to Step 4 Go to Step 5
4 Check coolant level. Refer to 3.2 Coolant
Maintenance in this Section. Low Go to Step 10 Go to Step 6
5
Check coolant filler cap. Refer to 3.7 Pressure
Testing – Coolant Filler Cap Pressure Testing in this
Section OK? Go to Step 8
Replace
Coolant filler
cap
6 Check thermostat. Refer to 3.8 Thermostat in this
Section. OK? Go to Step 9 Go to Step 13
7
Check Engine Coolant Temperature (ECT) sensor.
Refer to 6C1 Engine Management General Information. Faulty Replace Go to Step 12
8
Check cooling fan operation. Refer to 6C1 Engine
Management General Information. Operational Go to Step 10 Repair
9
Check for collapsed upper or lower radiator hose. Collapsed Replace Go to Step 13
10 Visual system check Leaks Go to Step 13 Go to Step 11
11 Check coolant concentration. Refer to 3.2 Coolant
Maintenance. To Specification Go to Step 12 Correct
Concentration Level
12 Check radiator core for bent fins, dirt, bugs or other
obstructions. Obstructed Clean or
straighten Go to Step 14
13
Pressure Test cooling system. Refer to 3.7 Pressure
Testing in this Section. Leaks Repair System OK
14
If none of the above require repair, the problem is
complex or of a major nature.
Refer to 4.5 Problems Not Requiring Disassembly of
Cooling System or 4.6 Problems Requiring Disassembly
of Cooling System. – – –

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