Engine Noise - Daewoo G424 Gasoline Service Manual

Engine Noise

No definite rule or test will positively determine the
source of engine noise. Therefore, use the following
information only as a general guide to engine noise
diagnosis.
1. Use a timing light to determine if noise is timed
with engine rpm or one-half engine rpm. Noises
timed with engine rpm are related to crankshaft,
rods, pistons, piston pins or flywheel. Noises timed
to one-half engine rpm are valve-train related.
2. The use of a stethoscope can aid in locating a
noise source. However, because noise will travel
to other metal parts not involved in the problem,
caution must be exercised.
3. If noise is believed to be confined to one particular
cylinder, ground the spark plug leads one at a
time. If noise lessens noticeably or disappears, it is
isolated to that particular cylinder.
Symptom
1. Noise around the
valve cover area.
2. Noise around the
cylinder area.
3. Noise around camshaft
area (throughout engine).
4. Noise in camshaft area
area (front of engine).
G424 Service Manual
4. Try to isolate the noise to location in engine, front
5. Sometimes noises can be caused by moving parts
6. When noise is isolated to a certain area and
Cause
A. Rocker arm striking valve cover.
B. Rocker arm out of adjustment.
C. Worn rocker arm.
D. Bent push rod.
E. Collapsed lifter.
A. Sticking valve.
B. Carbon build-up.
C. Connecting rod installed wrong.
D. Bent connecting rod.
E. Piston.
F. Piston rings.
G. Piston pin.
H. Cylinder worn.
A. Loss of oil pressure.
B. Valve lifters.
C. Cam bearings.
A. Camshaft timing gear.
B. Timing Belt.
C. Valve lifter.
D. Cam bearings.
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to back, top to bottom. This can help determine
which components are at fault.
coming in contact with other components.
Examples are: flywheel, crankshaft striking (pan
and pan baffle), rocker arm striking valve cover or
loose flywheel cover. In many cases, if this is
found to be the problem, a complete engine
teardown is not necessary.
component, removal and inspection will be
required. Refer to proper sections of service
manual for pertinent information.
Adjustment and Troubleshooting