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Home >> Subaru >> 2005 >> Outback R VDC Limited >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 17 (Engine Mechanical (H4DOTC)) >> Engine Noise >> Inspection

Engine Noise: Inspection

WARNING: This page is about a different variant/trim than selected.
POSSIBLE CAUSE CHART

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.
  • Loose flywheel mounting bolts
  • Damaged engine mounting
High-pitched clank 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 cylinder is disconnected. ((1))
  • Worn crankshaft 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 cylinder is disconnected. ((1))
  • 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 disconnected in turn. ((1))
  • Unusually worn valve lifter
  • Worn cam sprocket
  • Worn camshaft journal bore in crankcase
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 -
  • Loss of compression
  • Air leakage in air intake system, hoses, connections or manifolds
Timing belt noise -
  • Loose timing belt
  • Belt contacting case/adjacent part
Valve tappet noise -
  • Incorrect valve clearance
NOTE:
(1) 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 CLEAR MEMORY MODE , and INSPECTION MODE , after connecting the fuel injector connector.
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