600 Troubleshooting of engine (S-mode)
S-15 Unusual noise is made
40-600 22 PC200, 200LC, 220, 220LC-8M0
SEN06140-00
S-15 Unusual noise is made
General causes why unusual noise is heard
q Abnormality due to defective parts
q Abnormal combustion
q Air sucked in from air intake system
a Judge if the noise is an internal noise or an external noise before starting troubleshoot-
ing.
a The engine is operated in the low-temperature mode while it is not warmed up suffi-
ciently. Accordingly, the engine sound becomes a little larger. This does not indicate
abnormality, however.
a When the engine is accelerated, it is operated in the acceleration mode and its sound
becomes a little larger for up to about three seconds. This does not indicate abnormal-
ity, however.
Cause
Air leak at tubing between turbocharge and cylinder head
Seizure or interference at turbocharger
Damage of valve system (valve or rocker lever)
Defective inside of muffler (partition board out of position)
Improper valve clearance
Excessively worn piston ring or cylinder
Improper gear train backlash
Dislocated or seized bushing
Deformed cooling fan, loose fan belt, interference of fan belt
Clogged or seized injector
Dirt caught in injector
Improper fuel injection timing
(defect in low coolant temperature sensor or boost temperature sensor)
Questions
Check recent repair history.
Machine opera-
tion hours
Operated for long period
E
Abnormal noise
Gradually occurred.
QQ
Sudden occurred.
QQ Q
Fuel other than specified one is used
Q
Engine oil must be added more frequently.
w
Metal particles are found in the removed oil filter.
ww
Air leaks at tubing between turbocharger and cylinder head.
w
Check items
While engine is running, interference sound is heard from turbocharger.
w
While engine is running, unusual noise is heard around cylinder head.
ww
While engine is running, beat noise is heard around muffler.
w
When exhaust manifold is touched immediately after starting engine, temperature of
some cylinders is low.
wQ
Color of exhaust
smoke:
Blue under light load
w
Black
Qw Q
Engine does not pick up smoothly and combustion is irregular.
w
Unusual noise is loud when engine is accelerated
QQQQ
Blowby gas is excessive
w
Troubleshooting
When turbocharger is rotated by hand, it is found to be heavy.
q
Check valve system.
q
If muffler is removed, unusual noise disappears.
q
Check valve clearance.
q
When compression pressure measured, it is found to be low.
q
Check gear train.
qq
Check fan and fan belt.
q
Even if a cylinder is cut out, engine speed does not change.
qq
Unusual noise is heard only when engine is cranked.
q
Check the condition by using monitoring function of machine monitor.
q
Remedy
Replace
Replace
Replace
Replace
Adjust
Replace
Replace
Replace
Repair
Replace
Replace
Replace
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