Komatsu ecot3 PC300-8, Shop Manual

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40 Troubleshooting SEN02634-02
PC300, 350-8
23
S-16 Vibration is excessive 1
General causes why vibration is excessive
• Defective parts (abnormal wear, breakage)
• Misalignment between engine and chassis
• Abnormal combustion
a
If abnormal noise is made and vibration is excessive, carry out trouble-
shooting for “S-15 Abnormal noise is made”, too.
Cause
S
tuck dynam
ic val
v
e sys
te
m
(v
al
v
e
, rock
er l
e
v
e
r)
W
orn m
ain be
aring,
connec
ti
ng r
od bear
ing
Im
proper
gear
tr
ain back
lash
Worn c
a
ms
haf
t bu
shing
Im
proper
inject
io
n
t
im
ing (A
bnorm
a
lit
y
in
coolant
t
e
mpe
rat
ur
e sens
or
,
bo
ost
t
e
mperat
ure sensor
)
Loose engine mount
ing
bolt
s
, brok
en
c
ushions
Mis
a
lignm
ent
bet
ween
eng
ine and devices on
applic
able m
ac
hine
s
ide
Br
oken
out
put
s
h
af
t,
p
a
rt
s
in dam
p
er o
n
applicable
mach
in
e
side
Q
ues
ti
ons
Confirm recent repair history
Degree of use of
machine
Operated for long period
E E E
Condition of
vibration
Suddenly increased
Q Q
Gradually increased
Q Q Q
Non-specified oil is being used
Q Q
Metal particles are found when oil filter is drained
w w
Metal particles are found when oil pan is drained
w w
C
h
e
ck i
tem
s Oil pressure is low at low idle
Q Q
Vibration occurs at mid-range speed
Q Q
Vibration follows engine speed
Q Q Q Q
Exhaust smoke is black
w Q
T
roubleshoot
ing
Inspect dynamic valve system directly
q
Inspect main bearing and connecting rod bearing directly
q
Inspect gear train directly
q
Inspect camshaft bushing directly
q
Check with monitoring function of machine monitor
q
Inspect engine mounting bolts and cushions directly
q
When alignment is checked, radial runout or facial runout is detected
q
Inspect output shaft or inside of damper directly
q
Remedy
Replace Replace Replace Replace Replace Replace Adj
u
s
t
Replace