Ford 2003 Mustang Workshop Manual page 2014

Symptom Chart
Condition
Drive belt
noise, chirping,
flutter
Premature
drive belt wear
Component Tests
Drive Belt Noise/Flutter
Drive belt chirp occurs due to pulley misalignment or excessive pulley runout. It can be the result of a
damaged pulley or an incorrectly aligned pulley.
To correct, determine the area where the noise comes from. Check each of the pulleys in that area
with a straightedge to the crankshaft pulley, looking for accessory pulleys out of position in the fore/aft
direction or at an angle to the straightedge.
Drive belt squeal is an intermittent noise that occurs when the drive belt slips on a pulley during certain
conditions, such as: engine start up, rapid engine acceleration, or A/C clutch engagement.
Drive belt squeal can occur:
if any of the accessories are damaged, have a worn or damaged bearing, internal torsional
resistance above normal. All accessories should be rotatable by hand in the unloaded condition.
If not, inspect the accessory.
if fluid gets on the drive belt. This includes power steering fluid, engine coolant, engine oil or air
conditioning system lubricant. If fluid does get on the drive belt during service, clean the drive
belt with soap and water and thoroughly rinse with clean water.
NOTE: The drive belt tensioner arm should rotate freely without binding.
if the drive belt is too long. A drive belt that is too long will allow the drive belt tensioner arm to
go all the way to the arm travel stop under certain load conditions, which will release tension to
the drive belt. If the drive belt tensioner indicator is outside the installation wear range window,
install a new drive belt.
if the drive belt tensioner is worn or damaged.
Belt Tension
NOTE: Drive belt tension is not adjustable.
The drive belt tensioner automatically adjusts drive belt tension.
Possible Sources
Defective/worn drive
belt.
Misaligned pulley.
Pulley runout.
Damaged
accessories.
Fluid contamination
of drive belt.
Damaged or worn
drive belt tensioner.
Defective drive belt.
Misaligned pulley.
Pulley runout.
Damaged
accessories.
Incorrectly installed
drive belt.
Action
GO to Component Tests, Drive
Belt, Noise/Flutter.
GO to Component Tests, Belt
Tensioner, Automatic.
GO to Component Tests, Drive
Belt Noise/Flutter and Drive
Belt Misalignment diagnosis.