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Engine Noise: Inspection

WARNING: This page is about a different variant/trim than selected.
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 noise when engine speed is between 1, 000 and 2, 000 r/min Sound is reduced when the fuel injector connector of the noisy cylinder is disconnected.(1)
  • Worn crankshaft main bearing
  • Worn connecting rod bearing (large end)
Knocking sound when engine is operating under idling speed and engine is warm Sound is reduced when the fuel injector connector of the 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 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
(1) When disconnecting the fuel injector connector, the malfunction indicator light illuminates and DTC is stored in ECM memory.

Therefore, perform the Clear Memory Mode Refer to ENGINE (DIAGNOSTICS) (STI)>CLEAR MEMORY MODE>OPERATION . and inspection mode Refer to ENGINE (DIAGNOSTICS) (STI)>INSPECTION MODE>PROCEDURE . after connecting the fuel injector connector.

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