NVH Troubleshooting Chart Ð Engine Noise
Use the chart below to help you ®nd the cause of the problem.
1. Locate the area where noise occurs.
2. Con®rm the type of noise.
3. Specify the operating condition of engine.
4. Check speci®ed noise source.
If necessary, repair or replace these parts.
Location of
noiseType of
noiseOperating condition of engine
Source of
noiseCheck itemReference
page Before
warm-upAfter
warm-upWhen
startingWhen
idlingWhen
racingWhile
driving
To p o f
engine
Rocker
cover
Cylinder
headTicking or
clickingCAÐABÐTappet
noiseValve clearance EM-41
Rattle C A Ð A B CCamshaft
bearing
noiseCamshaft journal clearance
Camshaft runoutEM-37
Crankshaft
pulley
Cylinder
block (Side
of engine)
Oil panSlap or
knockÐAÐB BÐPiston pin
noisePiston and piston pin clear-
ance
Connecting rod bushing
clearanceEM-47, 53
Slap or rap A Ð Ð B B APiston slap
noisePiston-to-bore clearance
Piston ring side clearance
Piston ring end gap
Connecting rod bend and
torsionEM-48, 49
Knock A B C B B BConnecting
rod bearing
noiseConnecting rod bushing
clearance (Small end)
Connecting rod bearing
clearance (Big end)EM-52, 53
Knock A B Ð A B CMain bear-
ing noiseMain bearing oil clearance
Crankshaft runoutEM-51
Timing belt
coverWhine or
hissingCAÐAAÐTiming belt
noise (too
tight)
Loose timing belt
Belt contacting caseEM-18
Clatter A B Ð C A ÐTiming belt
noise (too
loose)
Front of
engineSqueaking
or ®zzingABÐBÐCOther drive
belts
(Sticking or
slipping)Drive belts de¯ection
*1
CreakingABABABOther drive
belts (Slip-
ping)Idler pulley bearing operation
Squall
CreakABÐBABWater pump
noiseWater pump operation *2
A: Closely related B: Related C: Sometimes related Ð: Not related
*1: MA section (``Checking Drive Belts'', ``ENGINE MAINTENANCE'')
*2: LC section (``Water Pump Inspection'', ``ENGINE COOLING SYSTEM'')
NOISE, VIBRATION AND HARSHNESS (NVH) TROUBLESHOOTING
EM-8
