ME(H4DOTC)-108
Engine Noise
MECHANICAL
26.Engine Noise
A: INSPECTION
(NOTE*)
When disconnecting the fuel injector connector, the malfunction indicator light illuminates and DTC is stored in ECM memory.
Therefore, perform the Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-54, OPERATION, Clear Memory Mode.> and Inspec-
tion Mode <Ref. to EN(H4DOTC)(diag)-43, PROCEDURE, Inspection Mode.> after connecting the fuel injector connector.
Type of sound
Condition
Possible cause
Regular clicking sound
Sound increases as engine
speed increases.
• Valve mechanism is defective.
• Incorrect valve clearance
• Worn camshaft
• Broken valve spring
Heavy and dull clank
Oil pressure is low.
• Worn crankshaft main bearing
• Worn connecting rod bearing (large end)
Oil pressure is normal.
• Loosened flywheel mounting bolt
• Damaged engine mounting
High-pitched clank
Sound is noticeable when
accelerating with an overload
condition.
• Ignition timing advanced
• Accumulation of carbon inside combustion chamber
• Wrong heat range of spark plug
• Improper octane value gasoline
Clank when engine speed is
between 1,000 and 2,000
rpms.
Noise is reduced when fuel
injector connector of noisy cyl-
inder is disconnected.
(NOTE*)
• Worn crankshaft main bearing
• Worn connecting rod bearing (large end)
Knocking sound when engine
is operating under idling speed
and engine is warm
Noise 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*)
• Unusually worn valve lifter
• Worn cam sprocket
• Worn camshaft journal bore in cylinder head
Squeaky sound
—
Insufficient generator lubrication
Rubbing sound
—
Poor contact of generator brush and rotor
Gear scream when starting
engine
—
• Defective ignition starter switch
• Worn gear and starter pinion
Sound like polishing glass with
a dry cloth
—
• Loose V-belt
• Defective water pump shaft
Hissing sound
—
• Insufficient compression
• Air leakage in air intake system, hose, connection or manifold
Timing belt noise
—
• Loose timing belt
• Timing belt contacting with adjacent part
Valve noise
—
Incorrect valve clearance
Summary of Contents for 2009 IMPREZA
Page 18: ...PC 4 Precaution PRECAUTION...
Page 21: ...NT 4 Note NOTE Lift Rigid rack A Attachment NT 00241 A A Attachment NT 00242 A...
Page 23: ...NT 6 Note NOTE A Front B Rear 1 Front crossmember 2 Rear differential 1 2 A B NT 00210...
Page 66: ...PI 22 Pre delivery Inspection PRE DELIVERY INSPECTION...
Page 112: ...PM 48 A C Filter PERIODIC MAINTENANCE SERVICES...
Page 219: ...IN H4SO 10 Resonator Chamber INTAKE INDUCTION...
Page 324: ...ME H4SO 106 Engine Noise MECHANICAL...
Page 388: ...SP H4SO 6 Accelerator Pedal SPEED CONTROL SYSTEMS...
Page 395: ...IG H4SO 8 Spark Plug Cord IGNITION...
Page 418: ...SC H4SO 24 Battery STARTING CHARGING SYSTEMS...
Page 725: ...EN H4SO diag 308 General Diagnostic Table ENGINE DIAGNOSTICS...
Page 926: ...GD H4SO 202 Diagnostic Trouble Code DTC Detecting Criteria GENERAL DESCRIPTION...
Page 1181: ...EX H4DOTC 16 Muffler EXHAUST...
Page 1212: ...CO H4DOTC 32 Engine Cooling System Trouble in General COOLING...
Page 1221: ...IG H4DOTC 8 Ignition Coil IGNITION...
Page 1818: ...GD H4DOTC 230 Diagnostic Trouble Code DTC Detecting Criteria GENERAL DESCRIPTION...
Page 2154: ...5MT 82 General Diagnostic Table MANUAL TRANSMISSION AND DIFFERENTIAL...
Page 2227: ...RS 20 General Diagnostic Table REAR SUSPENSION...
Page 2364: ...DS 36 General Diagnostic Table DRIVE SHAFT SYSTEM...
Page 2615: ...BR 48 General Diagnostic Table BRAKE...
Page 2624: ...PB 10 General Diagnostic Table PARKING BRAKE...
Page 2681: ...PS 58 General Diagnostic Table POWER ASSISTED SYSTEM POWER STEERING...
Page 2730: ...AC 50 General Diagnostic Table HVAC SYSTEM HEATER VENTILATOR AND A C...
Page 2961: ...SB 22 Rear Seat Belt SEAT BELT SYSTEM...
Page 3035: ...COM 6 Horn Switch COMMUNICATION SYSTEM...
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Page 3158: ...SL 54 Immobilizer Antenna SECURITY AND LOCKS...
Page 3167: ...SR 10 Sunshade SUNROOF T TOP CONVERTIBLE TOP SUNROOF...
Page 3240: ...EI 74 Ornament EXTERIOR INTERIOR TRIM...
Page 3286: ...CC 12 Neutral Position Switch CRUISE CONTROL SYSTEM...
Page 3311: ...CC diag 26 Diagnostic Procedure with Cancel Code CRUISE CONTROL SYSTEM DIAGNOSTICS...
Page 3421: ...LAN diag 88 General Diagnostic Table LAN SYSTEM DIAGNOSTICS...
Page 3486: ...WI 67 Remote Engine Start System WIRING SYSTEM...