Subaru Forester Engine 1999 2000 (16) PDF

2. Engine Noise
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 cyl-
inder is disconnected.
(NOTE*)
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 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 gear
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 engine coolant 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*:
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 2-7 [T3D0].> and INSPECTION MODE <Ref. to 2-7 [T3E0].> after con-
necting fuel injector connector.
64
2-3 [K200] DIAGNOSTICS
2. Engine Noise

Subaru Forester Engine 1999 2000 (16) Summary of Content

2. Engine NoiseType of sound Condition Possible causeRegular clicking soundSound increases as enginespeed increases. Valve mechanism is defective. Incorrect valve clearance Worn valve rocker Worn camshaft Broken valve springHeavy and dull clankOil pressure is low. Worn crankshaft main bearing Worn connecting rod bearing (big end)Oil pressure is normal. Loose flywheel mounting bolts Damaged engine mountingHigh-pitched clank (Sparkknock)Sound is noticeable whenaccelerating with an overload. Ignition timing advanced Accumulation of carbon inside combustion chamber Wrong spark plug Improper gasolineClank when engine speed ismedium (1,000 to 2,000 rpm).Sound is reduced when fuelinjector connector of noisy cyl-inder is disconnected.(NOTE*) Worn crankshaft main bearing Worn bearing at crankshaft end of connecting rodKnocking sound when engineis operating under idling speedand engine is warmSound is reduced when fuelinjector 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 rodSound is not reduced if eachfuel injector connector is dis-connected in turn. (NOTE*) Unusually worn valve lifter Worn cam gear Worn camshaft journal bore in crankcaseSqueaky sound Insufficient generator lubricationRubbing sound Defective generator brush and rotor contactGear scream when startingengine Defective ignition starter switch Worn gear and starter pinionSound like polishing glass witha dry cloth Loose drive belt Defective engine coolant pump shaftHissing sound Loss of compression Air leakage in air intake system, hoses, connections ormanifoldsTiming belt noise Loose timing belt Belt contacting case/adjacent partValve tappet noise Incorrect valve clearanceNOTE*:When disconnecting fuel injector connector, Malfunction Indicator Light (CHECK ENGINE light) illuminates and trouble code isstored in ECM memory.Therefore, carry out the CLEAR MEMORY MODE Ref. to 2-7 [T3D0]. and INSPECTION MODE Ref. to 2-7 [T3E0]. after con-necting fuel injector connector.642-3 [K200] DIAGNOSTICS2. Engine Noise