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INSPECTION

INSPECTION

Type of sound Condition Possible cause
Regular clicking sound

Sound increases as engine speed increases.


• Valve mechanism is defective.

• 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 (big 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 cylinder 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 cylinder 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 disconnected in turn. (NOTE*)


• 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 with case/adjacent part


Valve tappet noise

—

Incorrect valve clearance


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 and inspection mode after connecting the fuel injector connector.