Subaru Legacy (2005 year). Manual - part 78
ME(H4SO 2.0)-95
MECHANICAL
Engine Noise
27.Engine Noise
A: INSPECTION
NOTE*)
When disconnecting the fuel injector connector, the malfunction indicator light illuminates and DTC is stored in ECM memory.
Therefore, carry out the clear memory mode <Ref. to EN(H4SO 2.0)(diag)-38, OPERATION, Clear Memory Mode.> <Ref. to
EN(H4SO 2.5)(diag)-40, OPERATION.> and inspection mode <Ref. to EN(H4SO 2.0)(diag)-32, PROCEDURE, Inspection
Mode.> <Ref. to EN(H4SO 2.5)(diag)-2, PROCEDURE.> after connecting the fuel injector connector.
Type of sound
Condition
Possible cause
Regular clicking sound
Sound increases as engine
speed increases.
• Defective valve mechanism
• Incorrect valve clearance
• Worn valve rocker
• Worn camshaft
• Broken valve spring
Heavy and dull clank
Oil pressure is low.
• Worn camshaft main bearing
• Worn connecting rod bearing (large end)
Oil pressure is normal.
Damaged engine mounting
High-pitched clank (Spark
knock)
Sound is noticeable when
accelerating with an overload.
• Ignition timing advanced
• Accumulation of carbon inside combustion chamber
• Wrong spark plug
• Improper gasoline
Clank when engine speed is
1,000 to 2,000 rpm
Sound is reduced when fuel
injector connector of noisy cyl-
inder is disconnected.
(NOTE*)
• Worn camshaft main bearing
• Worn bearing at crankshaft end of connecting rod
Knocking sound when engine
is operating under idling speed
and engine is warm
Sound is reduced when fuel
injector connector of noisy cyl-
inder is disconnected.
(NOTE*)
• Worn cylinder liner and piston ring
• Broken or stuck piston ring
• Worn piston pin and hole at piston end of connecting rod
Sound is not reduced if each
fuel injector connector is dis-
connected in turn. (NOTE*)
• Worn cam sprocket
• Worn camshaft journal bore in cylinder head assembly
Squeaky sound
—
Insufficient generator lubrication
Rubbing sound
—
Defective generator brush and rotor contact
Gear scream when starting
engine
—
• Defective ignition starter switch
• Worn gear and starter pinion
Sound like polishing glass with
a dry cloth
—
• Loose drive belt
• Defective water pump shaft
Hissing sound
—
• Insufficient compression
• Air leakage in air intake system, hoses, connections or mani-
folds
Timing belt noise
—
• Loose timing belt
• Belt contacting with case/adjacent part
Valve tappet noise
—
Incorrect valve clearance