Unusual Noise Is Made - Komatsu PC200-8M0 Shop Manual

SEN06140-00
S-15 Unusual noise is made
General causes why unusual noise is heard
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Abnormality due to defective parts
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Abnormal combustion
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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.
Check recent repair history.
Machine opera-
Operated for long period
tion hours
Gradually occurred.
Abnormal noise
Sudden occurred.
Fuel other than specified one is used
Engine oil must be added more frequently.
Metal particles are found in the removed oil filter.
Air leaks at tubing between turbocharger and cylinder head.
While engine is running, interference sound is heard from turbocharger.
While engine is running, unusual noise is heard around cylinder head.
While engine is running, beat noise is heard around muffler.
When exhaust manifold is touched immediately after starting engine, temperature of
some cylinders is low.
Blue under light load
Color of exhaust
smoke:
Black
Engine does not pick up smoothly and combustion is irregular.
Unusual noise is loud when engine is accelerated
Blowby gas is excessive
When turbocharger is rotated by hand, it is found to be heavy.
Check valve system.
If muffler is removed, unusual noise disappears.
Check valve clearance.
When compression pressure measured, it is found to be low.
Check gear train.
Check fan and fan belt.
Even if a cylinder is cut out, engine speed does not change.
Unusual noise is heard only when engine is cranked.
Check the condition by using monitoring function of machine monitor.
22
40-600
600 Troubleshooting of engine (S-mode)
S-15 Unusual noise is made
Cause
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Remedy
PC200, 200LC, 220, 220LC-8M0
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