04-4
2. INSPECTION
1) Troubleshooting
When Abnormal Noises are Heard from the Engine Room ▶
For the vehicle equipped with DI engine, if a learning noise occurs in each range or other
noises occur, the major cause of it is a faulty turbocharger assembly. But an interference
issue, poor tightness or loose in the intake and exhaust system also can cause those noises.
This is mainly because the operator didn't follow the instruction exactly when reconnecting
the intake hoses and pipes which were disconnected to check the system or replace the air
cleaner. If the intake system is free of any faults, check the EGR and PCV oil separator
connected to the intake system.
The figure may be different from the actual engine. Therefore, read thoroughly below before
replacing the parts.
2) Abnormal Noise Caused by Poor Tightness of Intake System
When the DI engine is running, the air entered into the engine flows in the sequence as shown
above. If high intake pressure is applied to the loose or damaged part, a whistling noise may
occur, the intake air volume is measured incorrectly or the engine power is derated.
04-51719-00
3) Troubleshooting Sequence
The basic checks for intake system are as follows:
Basic Checks for Intake System ▶
Make sure to replace or clean the air cleaner
element periodically. Otherwise, engine will be
derated or work abnormally because of low
intake air volume.
Unlike the fuel system, which is a closed
circuit, the intake system is an open circuit
system. Therefore any malfunction may occur
due to dust and dirt.
Most of the connections consist of hoses so
the system cannot withstand high temperature
and pressure. Also it can be deformed or
loosened easily because it is a clamp
mounting system. Thus, when checking the
engine, basic inspections, such as tightened
status check and visual inspection for hose,
etc., should be carried out in advance.
Other Checks for Intake System ▶
If the intake system is free of any faults,
check for EGR and PCV oil separator.
05-4
2. CAUTIONS
Do not park the vehicle on flammable materials, such as grass, leaves and carpet.
Do not touch the catalyst or the exhaust gas ignition system when the engine is running.
If a misfire occurs in the combustion chamber or the emission of pollutant exceeds the
specified level, the catalyst can be damaged.
When servicing or replacing components of the exhaust system, makes sure that the
components are positioned at regular intervals from all other parts of the under body.
Be careful not to damage the exhaust system when lifting the vehicle from its side.
All components and body parts of the engine exhaust system should be inspected for crack,
damage, air hole, part loss and incorrect mounting location. Also check for any deformation
which can result in exhaust gas drawn into the vehicle.
Make sure that the exhaust pipe is cooled down sufficiently before working on it because it is
still hot right after the engine is stopped.
Wear protective gloves when removing the exhaust pipe. -
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06-4
2. INSPECTION
1) Cautions During Driving
The following lists cautions to take during test drive and on the turbocharger vehicle, which must
be considered during the operation.
It's important not to drastically increase the engine rpm starting the engine. It could make
rotation at excessive speed even before the journal bearing is lubricated and when the
turbocharger rotates in poor oil supply condition, it could cause damage of bearing seizure
within few seconds.
If the engine is running radically after replacing the engine oil or oil filter brings poor oil supply
condition. To avoid this, it's necessary to start off after idling the engine for about 1 minute
allowing oil to circulate to the turbocharger after the replacement.
When the engine is stopped abruptly after driving at high speed, the turbocharger continues to
rotate in condition where the oil pressure is at '0'. In such condition, an oil film between the
journal bearing and the housing shaft journal section gets broken and this causes abrasion of
the journal bearing due to the rapid contact. The repeat of such condition significantly reduces
life of the turbocharger.
Therefore, the engine should be stopped possibly in the idle condition. 1.
2.
3.
After string for long period of time during winter season or in the low temperature condition
where the fluidity of engine oil declines, the engine, before being started, should be cranked
to circulate oil and must drive after checking the oil pressure is in normal condition by idling
the engine for few minutes.
06-51914-01
2) Inspection of Turbocharger
When problem occurs with the turbocharger, it could cause engine power decline, excessive
discharge of exhaust gas, outbreak of abnormal noise and excessive consumption of oil.
On-board Inspection 1.
Check the bolts and nuts foe looseness or missing
Check the intake and exhaust manifold for looseness or damage
Check the oil supply pipe and drain pipe for damages
Check the housing for crack and deterioration -
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Inspection of turbine 2.
Remove the exhaust pipe at the opening of the turbine and check, with a lamp, the existence of
interference of housing and wheel, oil leakage and contamination (at blade edge) of foreign
materials.
Interference: In case where the oil leak sign exists, even the small traces of interferences on
the turbine wheel mean, most of times, that abrasion has occurred on the journal bearing.
Must inspect after overhauling the turbocharger.
Oil Leakage: Followings are the reasons for oil leakage condition -
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Problems in engine: In case where the oil is smeared on inner wall section of the exhaust
gas opening.
Problems in turbocharger: In case where the oil is smeared on only at the exhaust gas
outlet section. *
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Idling for long period of time can cause oil leakage to the turbine side due to low pressure of
exhaust gas and the rotation speed of turbine wheel. Please note this is not a turbocharger
problem.
Oil Drain Pipe Defect
In case where oil flow from the turbocharger sensor housing to the crank case is not smooth
would become the reason for leakage as oil builds up within the center housing. Also, oil
thickens (sludge) at high temperature and becomes the indirect reason of wheel hub section.
In such case, clogging and damage of the oil drain pipe and the pressure of blow-by gas
within the crank case must be inspected.
Damages due to Foreign Materials.
When the foreign materials get into the system, it could induce inner damage as rotating
balance of the turbocharger gets out of alignment. -
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06-6
3) Inspection of Turbine
Thoroughly check the followings.
Must absolutely not operate the turbocharger with the compressor outlet and inlet opened as it
could damage the turbocharger or be hazardous during inspection.
Interference: In case where is trace of interference or smallest damage on the compressor
wheel means, most of times, that abrasion has occurred on the journal bearing. Must inspect
after the overhaul.
Oil Leakage: The reason for oil leakage at the compressor section is the air cleaner, clogged
by substances such as dust, causes the compressor inlet negative pressure. -
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Rotating in high speed at no-load for extended period of time can cause oil leakage to the
compressor section as oil pressure within the center housing gets higher than pressure
within the compressor housing.
Overuse of engine break (especially in low gear) in down hill makes significantly low
exhaust gas energy compared to the time where great amount of air is required during
idling conditions of the engine. Therefore, amount of air in the compressor inlet increases
but the turbocharge pressure is not high, which makes negative a.
b.
No problem will occur with the turbocharger if above conditions are found in early stage but oil
leaked over long period of time will solidify at each section causing to breakout secondary
defects.
Damages by foreign materials: In case where the compressor wheel is damaged by foreign
materials requires having an overhaul. At this time, it's necessary to check whether the foreign
materials have contaminated intake/exhaust manifold or inside of engine.
06-111914-01
3. TROUBLESHOOTING
The followings are cautions to take in handling defects of turbocharger, which must be fully aware
of.
1) Cautions
After stopping the engine, check whether the bolts on pipe connecting section are loose as
well as the connecting condition of vacuum port and modulator, which is connected to the
actuator.
During idling of the engine, check for leakage in the connecting section of pipe (hoses and
pipes, duct connections, after the turbocharger) by applying soap water. The leakage condition
in the engine block and turbine housing opening can be determined by the occurrence of
abnormal noise of exhaust.
By running the engine at idle speed, abnormal vibration and noise can be checked.
Immediately stop the engine when abnormal vibration and noise is detected and make
thorough inspection whether the turbocharger shaft wheel has any damages as well as
checking the condition of connections between pipes.
In case where the noise of engine is louder than usual, there is possibility of dampness in the
areas related with air cleaner and engine or engine block and turbocharger. And it could affect
the smooth supply of engine oil and discharge.
Check for damp condition in exhaust gas when there is sign of thermal discoloration or
discharge of carbon in connecting area of the duct.
When the engine rotates or in case where there is change in noise level, check for clogging of
air cleaner or air cleaner duct or if there is any significant amount of dust in the compressor
housing.
During the inspection of center housing, inspect inside of the housing by removing the oil drain
pipe to check for sludge generation and its attachment condition at shaft area or turbine side.
Inspect or replace the air cleaner when the compressor wheel is damaged by inflow of foreign
materials.
Inspect both side of the turbocharger wheel after removing inlet and outlet pipe of the
turbocharger. 1.
2.
3.
4.
5.
6.
7.
8.
9.
07-31543-00
1. SPECIFICATION
The engine oil filter element should be changed at the same time with the engine oil.
Regularly check the engine oil level and add the engine oil if necessary.
Remember to check the engine oil level and shorten the cycle to replace the engine oil
under severe driving conditions. -
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Severe Driving Condition
Frequent stop-and-go traffic, extended idling, short driving distance below 6 km, driving
distance below 16 km when the outside temperature remains below freezing
Driving in a hilly or mountainous terrain, sandy, or dusty area
High load driving such as trailer towing
Taxi, patrol service or delivery service (extended idling and excessive driving with low speed) -
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Unit Specification
Oil pump Lubrication system Gear pump, forced circulation
Type Inscribed gear
Capacity 63 L at 4,000 rpm
Relief pressure5.8 bar ± 0.3 bar
Oil filter Type Full flow/Paper element
Engine oil Specified oil SAE 5W30 (approved by MB SHEET 229.51)
Capacity (L) Min.: 4.5 L
Max.: 6.0 L
Service
intervalEU Change every 20,000 km or 12 months
(The service interval should be shortened under
severe conditions)
General Change every 15,000 km or 12 months
(The service interval should be shortened under
severe conditions)
Oil injection nozzle Type Piston
Operating pressure 1.5bar
Closing pressure 1.0bar
Oil flow 4 L/min
Oil pressure switch Permissible pressure 10bar