2007 ISUZU KB P190 engine overheat

Engine Mechanical – V6 Page 6A1–205
Page 6A1–205
Inspect
Camshaft Visual Inspection
1 Inspect the threaded hole (2) for damage.
2 Inspect the camshaft spro cket locating notch (3) for
damage or wear.
3 Inspect the camshaft sealing grooves (4) for damage.
4 Inspect the camshaft thrust surface (5) for damage.
5 Inspect the camshaft lobes (6) and journals (7) for the following conditions:
• Excessive scoring or pitting
• Discoloration from overheating
• Deformation from excessive wear, especially
the camshaft lobes
6 If any of the above conditions exist on the camshaft, replace the camshaft.

Figure 6A1 – 336
Camshaft Measurement
1 With the camshaft (1) in a suitable fixture (2), measure the camshaft for wear.
2 For camshaft measurement, refer to the following specifications, 5 Specifications .

NOTE
If the camshaft measures outside the specified
range, replace the camshaft.
CAUTION
No machining of the camshaft is allowed.

Figure 6A1 – 337
3 Measure the camshaft (2) journals for diameter and out-of-round using an outsi de micrometer (1).


Figure 6A1 – 338

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Engine Mechanical – V6 Page 6A1–222
Page 6A1–222
Clean
CAUTION
Due to the aluminium alloy construction of
the cylinder head, wire brushes and steel
scrapers must not be used during the
cleaning process, as damage to sealing
surfaces may occur. Use a wood or plastic
scraper as an alternative.
1 Remove any old thread sealant, gasket material or seal ant using commercially available plastic or wooden scraper.
2 Clean all cylinder head surfaces with non-corrosive solvent.

Safety glasses must be worn when using
compressed air.
3 Blow out all the oil galleries using compressed air.
4 Remove any carbon deposits fr om the combustion chambers.
5 Clean any debris or build-up from the lifter pockets.
Inspect
Visual Inspection
1 Inspect the cylinder head (1) camshaft bearing surfaces for the following conditions:
• excessive scoring or pitting,
• discoloration from overheating, and
• deformation from excessive wear.
2 If any of the above conditions exist on the camshaft bearing surfaces, replace the cylinder head. Do not
machine the camshaft bearing journals.


Figure 6A1 – 377
3 Inspect the cylinder head for the following: • Cracks, damage or pitting in the combustion chambers.
• Debris in the oil galleries. continue to cl ean the galleries until all debris is removed.
• Coolant leaks or damage to the deck face sealing surfac e. if coolant leaks are present, measure the surface
warpage as described under Cylinder Head M easurement within this Section.
• Burrs or any defects that would degrade the sealing of a new secondar y camshaft chain tensioner gasket.
• Damage to any gasket surfaces.
• Damage to any threaded bolt holes.
• Burnt or eroded areas in the combustion chamber.
• Cracks in the exhaust ports and combustion chambers.
• External cracks in the water passages.
• Restrictions in the intake or exhaust passages.
• Restrictions in the cooling system passages.
• Rusted, damaged or leaking core plugs.
4 If the cylinder head is cracked or damaged, it must be r eplaced. No welding or patching of the cylinder head is
recommended.

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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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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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Engine Management – V6 – Diagnostics Page 6C1-2–29

Checks Actions
Preliminary Perform the preliminary checks. Refer to 4.3 Preliminary Checks in this Section.
Fuel System Inspect the injectors for leaking condition. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
Engine Cooling System • Check for engine overheating. Refer to 6B1 Engine Cooling – V6.
• Check the engine thermostat for proper operation and correct heat range. Refer to
6B1 Engine Cooling – V6.
Engine Mechanical • Check for build up of carbon deposit in the combustion chamber, which may
cause hot spots and increased compression ratio. Refer to 6A1 Engine
Mechanical – V6.
• Using Tech 2, check for incorrect engine idle speed.
Additional
• If the engine continues to run after the ignition is switched off but the engine runs
normally, check the following:
• ignition switch operation,
• voltage feedback from alternator L terminal to ignition switch, and
• sticking ignition control relay.
When all diagnosis and repairs are completed, check the system for correct operation.
5.8 Hard Start
Definition
The engine cranks normally but takes longer to start than usual. As soon as the engine runs, the engine may stall
immediately.
Checks Actions
Preliminary • Perform the preliminary checks. Refer to 4.3 Preliminary Checks in this
Section.
• Check the immobiliser system for correct operation. Refer to 11A Immobiliser.
Sensor / System
• Check the engine coolant temperature (ECT) sensor for an incorrect value.
Compare the engine coolant temperature against the intake air temperature (IAT)
on a cold engine. The ECT and IAT sensor values should be within ± 3°C of each
other. Refer to 6C1-3 Engine Management – V6 – Service Operations for details
of the Temperature vs. Resistance Table.
• Check the mass air flow (MAF) sensor installation. Incorrect installation of the
MAF sensor may cause hard start condition. Refer to 6C1-3 Engine Management
– V6 – Service Operations.
• Test the resistance of the crankshaft position (CKP) sensor. The CKP sensor
resistance must be within 700 – 1,200 Ω at all temperatures.
• Check for dirty starter motor commutator or brushes that can mask the crankshaft
position sensor signal.
Fuel System • Check the fuel system for the following fault conditions. Refer to 6C Fuel System
– V6.
• restricted fuel filter,
• incorrect fuel pressure, and
• contaminated fuel.
• Check the operation of the fuel injectors. Refer to 6C1-3 Engine Management –
V6 – Service Operations.

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Engine Management – V6 – Service Operations Page 6C1-3–50

• plug/s overheating due to insufficient tightening (caused by combustion gases leaking past the threads).
Broken Insulator
Broken insulators are usually the result of improper installation or carelessness.
Breaks in the upper insulator can result from a poor fitting spark plug socket or impact. The cracked insulator may not
show up until oil or moisture penetrates the crack. The crack is often just below the crimped part of the shell and may not
be visible.
Breaks in the lower insulator often result from careless re-gapping and are usually visible.
This can also result from the plug operating too hot. For example, in periods of high speed operation or under heavy
loads.

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Engine Management – V6 – Service Operations Page 6C1-3–52

Oil Fouled (3)
W et, oily deposits with minor electrode wear possibly due to oil leaking past worn piston rings.
Breaking in a new or recently overhauled engine before the rings are fully seated may also result in this condition.
Deposit Fouling A (4)
Red brown, yellow and white coloured coatings on the insulator tip which are by-products of combustion. They come
from fuel and lubricating oil which generally contain additives. Most powdery deposits have no adverse effect on spark
plug operation, however, they may cause intermittent missing under severe operating conditions.
Deposit Fouling B (5)
Deposits similar to those identified in deposit fouling A (4). These are also by-products of combustion from fuel and
lubricating oil. Excessive valve stem clearances and / or defective intake valve seals allow too much oil to enter the
combustion chamber. The deposits will accumulate on the portion of the spark plug that projects into the chamber and
will be heaviest on the side facing the intake valve. If this condition is only detected in one or two cylinders, check the
valve stem seals.
Deposit Fouling C (6)
Most powdery deposits identified in deposit fouling A (4) have no adverse effect on the operation of the spark plug as
long as they remain powdery.
Under certain conditions of operation however, these deposits melt and form a shiny glaze coating on the insulator.
W hen hot, this acts as a good electrical conductor allowing the current to flow along the deposit instead of sparking
across the gap.
Detonation (7)
Commonly referred to as engine knock or pinging, detonation causes severe shocks inside the combustion chamber
causing damage to parts.
Pre-ignition (8)
Burnt or blistered insulator tip and badly eroded electrodes probably due to the excessive heat.
This is often caused by a cooling system blockage, sticking valves, improperly installed spark plugs or plugs that are the
wrong heat rating (too hot).
Sustained high speed with a heavy load can produce temperatures high enough to cause pre-ignition.
Heat Shock Failure (9)
A rapid increase in spark plug tip temperature under severe operating conditions can cause heat shock and result in
fractured insulators. This is a common cause of broken and cracked insulator tips.
Insufficient Installation Torque (10)
Poor contact between the spark plug and the cylinder head seat.
The lack of proper heat transfer that results from poor seat contact causes overheating of the spark plug. In many cases,
severe damage occurs. Dirty threads in the cylinder head can cause the plug to seize before it is seated.
Ensure the cylinder head and spark plug threads are free of deposits, burrs and scale before installation.

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Battery Page 6D1-3–11

b W ait 15 seconds for the battery to recover.
8 If possible, set the selector to 50% of rapid discharge current (or three times the 20 hour discharge rate).
9 Apply the load test for 10 seconds and record the battery voltage. If one cell is faulty it will gas excessively or overheat. This indicates a faulty battery.
10 Recharge the battery if the voltage is at or below the minimum voltage specified by the HRD manufacturer (or 9.6 V).
11 Replace the battery if the voltage is below the minimum voltage specified by the HRD manufacturer (or below 9.6 V after the battery is charged and the test is repeated). Refer to 4.1 Battery.
12 Connect the battery positive terminal.
13 Connect the battery negative terminal.
Alternate Load Test
If HRD test equipment is not available, test the battery as follows:
1 Read and obey the safety precautions for working with batteries, refer to 2 Safety Precautions.
2 Ensure the state of the battery is at least 65% charged. Refer to 3.3 Hydrometer Test.
3 Connect a voltmeter (1) between the battery terminals.
4 Turn the headlights on to high-beam for 10 seconds to remove any surface charge from the battery.
5 Remove fuses EB11 and EB12 from the engine compartment fuse and relay housing. This prevents
vehicle ignition and fuel injection while cranking the
engine.
6 Crank the engine and read the voltmeter. At temperatures above 5°C, the voltage of a fully charged
battery should not fall below 9.6 V.
NOTE
• If the battery and engine temperatures are
below 5 °C, the voltage may fall to 9 V.
• Try to avoid activating the starter motor
continuously for more than 30 seconds. If
activating the starter motor for 30 seconds,
allow the starter motor to cool for 3 minutes.
7 Replace the battery if a cell gasses excessively or overheats or if the voltage falls away quickly.
Figure 6D1-3 – 6
3.5 Battery Current Draw Test
The following test determines if excess current is being drawn from the battery whilst the vehicle has all accessories
turned off. Excess current draw will cause the battery to go flat if the vehicle is not started for an extended period.
Test Preparation
1 Read and obey the safety precautions for working with batteries, refer to 2 Safety Precautions.
2 If the battery is flat, temporarily install a good battery for the duration of the test.
3 Ensure the vehicle starts and the accessories operate normally.
4 Ensure the theft deterrent system operates normally. Refer to 11A Immobiliser.
5 Open all the side windows for access purposes.
6 Switch the ignition off.
7 Check that all interior illumination is off, including any compartment lighting.
8 Close all doors.

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