Ford 2003 Mustang Workshop Manual page 76

(+40°F) or colder at
first start of the day
Power steering moan
— occurs at high idle
and possibly at idle
during the first cold
start of the day in
temperatures of
approximately -18°C
(0°F) or colder. Noise
can even be a severe
screech for less than
one minute in very
cold temperatures of
approximately -29°C
(-20°F) or colder
Generator whine —
during high electrical
loads at idle or high
idle, a high pitch
whine or moan is
emitted from the
generator
Engine-driven cooling
fan moan — occurs
during the first start of
the day. It is most
objectionable near
idle speeds up to
2000 rpm. The noise
increases with rpm
Drumming noise —
occurs inside the
vehicle during idle or
high idle, hot or cold.
Very low-frequency
drumming is very rpm
dependent
Hissing noise —
occurs during idle or
high idle that is
apparent with the
hood open
between ball
bearings and
bearing race.
High fluid
viscosity, or
plugged
reservoir screen
in power
steering
reservoir
starves pump
causing
cavitation.
Generator
electrical field
noise.
The viscous
cooling fan
clutch engages
until the fluid in
the clutch
reaches normal
operating
temperature,
causing the fan
to fully engage.
Exhaust system
vibration excites
the body
resonances
inducing interior
noise.
Engine vibration
excites the
body
resonances
inducing interior
noise.
Vacuum leak or
idle air control
(IAC) valve flow
noise.
Go To Pinpoint Test D
Using an EngineEAR,
PROBE near the generator
housing. LISTEN for
changes in the noise level
while changing electrical
loads (such as rear defrost,
headlamps, etc.). CARRY
OUT a generator load test. If
the system passes the load
test, the noise is from the
generator bearings,
INSTALL new bearings. If
the system fails the load
test, INSTALL a new
generator. REFER to
Section 414-02 .
Go To Pinpoint Test E
Go To Pinpoint Test F .
Use the Ultrasonic Leak
Detector/EngineEAR to
locate the source. Scan the
air intake system from the
inlet to each cylinder intake
.
.