- 28 -
LP Engine G430(3.0L) Troubleshooting
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.
4. Try to isolate the noise to location in engine, front to
back, top to bottom. This can help determine which
components are at fault.
5. Sometimes noises can be caused by moving parts
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.
6. When noise is isolated to a certain area and
component, removal and inspection will be
required. Refer to proper sections of service manual
for pertinent information.
Symptom Cause
1. Noise around the A. Rocker arm striking valve cover.
valve cover area. B. Rocker arm out of adjustment.
C. Worn rocker arm.
D. Bent push rod.
E. Collapsed lifter.
2. Noise around the A. Sticking valve.
cylinder area. B. Carbon build-up.
C. Connecting rod installed wrong.
D. Bent connecting rod.
E. Piston.
F. Piston rings.
G. Piston pin.
H. Cylinder worn.
3. Noise around camshaft A. Loss of oil pressure.
area (throughout engine). B. Valve lifters.
C. Cam bearings.
4. Noise in camshaft area A. Camshaft timing gear.
area (front of engine). B. Timing chain.
C. Fuel pump.
D. Valve lifter.
E. Cam bearings.
To Next Page
Loading...
Need help?
General
