Engine Noise - Subaru SVX 1992 Manual

ENGINE [T200) 2-3
2 . Engine Noise
Valve lash adjusters may make clicking noise once engine starts . It is normal if clicking noise ceases after a few
minutes .
If clicking noise continues after a few minutes, check engine oil level and add oil if necessary. Warm up engine for
five minutes, then drive it at approximately 3,000 rpm for twenty minutes . If noise still exists, conduct
troubleshooting procedures in accordance with the following table .
Type of sound Condition Possible cause
Valve mechanism is defective
Sound increases as engine speed
Broken and worn lash adjuster .
Regular clicking sound.
Worn camshaft .
increases .
Broken valve spring .
Worn lash adjuster guide.
Oil pressure is low .
Worn crankshaft main bearing .
Worn connecting rod bearing (big end) .
Heavy and dull metallic knock .
Oil pressure is normal
0 Loose flywheel mounting bolts.
a Damaged engine mounting .
Ignition timing advanced .
High-pitched metallic knock . (En- Sound is noticeable when accel- 0 Accumulation of carbon inside combustion chamber .
gine knocking) erating with an overload . a Wrong spark plug .
Improper gasoline .
Metallic knock when engine Sound is reduced when spark
e Worn crankshaft main bearing .
speed is medium (1,000 to 2,000 plug in noisy cylinder is short-
e Worn bearing at crankshaft end of connecting rod .
rpm) . ened out.
Sound is reduced when spark a Worn cylinder liner and piston ring .
plug in noisy cylinder is short- 0 Broken or stuck piston ring .
Knocking sound when engine
i
is
ened out.
* Worn piston pin and hole at piston end of connecting rod .
operating under idling speed and
engine is warm .
Sound is not reduced if each
* Unusually worn valve lifter .
spark plug is shortened out in o Worn cam gear .
turn .
* Worn camshaft journal bore in crankcase.
Squeaky sound . -
* Insufficient alternator lubrication .
Rubbing sound . - * Defective alternator brush and rotor contact.
Type of sound Condition Possible cause
Gear scream when starting en- e Defective ignition starter switch .
gine.
_
0 Worn gear and starter pinion .
Sound like polishing glass with a e Loose drive belt.
dry cloth.
_
* Defective water pump shaft .
* Loss of compression.
Hissing sound . - e Air leakage in air intake system, hoses, connections or mani-
folds.
Timing belt noise .
-
Loose timing belt.
0 Belt contacting case/adjacent part.
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