Komatsu 4D98 Series Shop Manual page 113

8. Turbocharger (for 4TNE106T)
8.8
Troubleshooting
Sufficient turbocharger performance and required engine output cannot be obtained if there is any
fault. In such a case, first check each engine part to see there is no engine fault. Then inspect the
turbocharger for troubleshooting according to the procedure shown below.
(1) Excessively exhaust smoke
<Insufficient intake air volume>
Cause
1) Clogged air cleaner element
2) Blocked air intake port
3) Leak from a joint in intake line
<Turbocharger revolution failure>
Corrective action
l
Replace or wash the element.
l
Correct to the normal state.
l
Inspect and repair.
Cause
1) Deposit of impurities in oil sticking on
the turbine side seal portion to make turbine
revolution heavy
2) Sticking bearing
l
Insufficient lubrication or clogged lubrication
piping
l
Excessively high oil temperature
l
Unbalanced rotating part
l
Insufficient warming up or sudden stop from
loaded operation (no-load operation)
3) Contact or breakdown of turbine wheel or
blower vane
l
Excessive revolution
l
Excessive exhaust temperature rise
l
Foreign matter invasion
l
Worn bearing
l
Assembly defect
Corrective action
l
Turbocharger overhaul (disassembly and
washing) with lubricating oil replacement
l
Turbocharger overhaul (disassembly and repair)
l
Lubricating oil line inspection, repair of defective
portion and lubricating oil replacement
l
Rotating part replacement or washing
l
Strict observance of instructions in operation
manual
. Inspection and repair of each engine part
l
Perfect foreign matter elimination in disassembled
state, followed by inspection and repair of
individual air cleaner and engine components
. Turbocharger overhaul (disassembly and repair)
l
Reassembly
<Influence of exhaust resistance>
Cause
Corrective action
1) Exhaust gas leak before the turbocharger to
l
Joint inspection and correction
decrease its revolutions
2) Deformed or clogged exhaust pipe to decrease
l
Correct to the normal state.
turbocharger revolutions
(2) White smoke generation
Cause
Corrective action
1) Clogged or deformed oil return pipe causing oil
0 Repair or pipe replacement
flow to the blower or turbine side
2) Excessive bearing wear causing abnormal wear
. Turbocharger disassembly and repair
or damage of seal ring
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8-17