Engine Noise: Inspection

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

ENGINE NOISE INSPECTION CHART

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 crankshaft main bearing
Worn connecting rod bearing (big end)

Oil pressure is normal.

Loose flywheel mounting bolts
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 medium (1,000 to 2,000 rpm).

Sound is reduced when fuel injector connector of noisy cylinder is disconnected.
(⁽¹⁾)

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.
(⁽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⁾)

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

Loss of compression
Air leakage in air intake system, hoses, connections or manifolds

Timing belt noise

Loose timing belt
Timing belt cover/adjacent part

Valve noise

Incorrect valve clearance

NOTE:

⁽¹⁾

When disconnecting fuel injector connector, Malfunction Indicator Light (CHECK ENGINE light) illuminates and trouble code is stored in ECM memory. Therefore, carry out the CLEAR MEMORY MODE < Ref. to CLEAR MEMORY MODE > and INSPECTION MODE < Ref. to INSPECTION MODE . > after connecting fuel injector connector.