2003 FORD MUSTANG suspension

z
If equipped, inspect automatic transmission fluid level with dipstick.
z Inspect brake pads, shoes, rotors, drums, brake lines, hoses and parking brake system.
z Inspect wheel ends for end play and noise.
z Inspect engine cooling system and hoses.
z Inspect steering linkage, suspension and (if equipped) driveshaft and ball joints.
z Rotate tires and inspect for wear.
z Install a new cabin air filter.
z If filled with green engine coolant, change coolant.
224,000 Km (140,000 Miles)
zChange engine oil and install a new oil filter.
z Inspect tires for wear. Rotation recommended for optimal tire life.
232,000 Km (145,000 Miles)
zChange engine oil and install a new oil filter.
z Inspect tires for wear. Rotation recommended for optimal tire life.
240,000 Km (150,000 Miles)
zChange engine oil and install a new oil filter.
z Inspect brake pads, shoes, rotors, drums, brake lines, hoses and parking brake system.
z Inspect wheel ends for end play and noise.
z Inspect engine cooling system and hoses.
z Inspect exhaust system and heat shields.
z Inspect steering linkage, suspension and (if equipped) driveshaft and ball joints.
z Rotate tires and inspect for wear.
z Install a new engine air filter.
z Install a new fuel filter. (See ADDITIONAL INFORMATION below.)
z If equipped, install a new cabin air filter.
z If filled with yellow engine coolant, change coolant or at 8 years, whichever comes first.
z Change automatic transmission/transaxle fluid and filter.
z Change rear axle lubricant on all rear wheel (RWD) vehicles.
z Install a new accessory drive belt(s) (if a new belt has not been installed within the last 100,000
miles).
z If equipped, install new climate controlled seat filters (Navigator, Lincoln LS and Aviator).
ADDITIONAL INFORMATION: If vehicle is registered in California, the California Air Resources Board
(CARB) has determined that failure to install a new fuel filter at this interval will not nullify the emission
warranty or limit recall liability prior to completion of the vehicle's useful life. It is, however
recommended that maintenance checks be carried out and recorded at the indicated intervals.
Additional checks for natural gas and propane vehicles include inspecting fuel tanks, as well as
draining and installing a new filter. Klj . 9 ba
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DESCRIPTION AND OPERATION
Noise, Vibration and Harshness (NVH)
Noise is any undesirable sound, usually unpleasant in nature. Vibration is any motion, shaking or
trembling, that can be felt or seen when an object moves back and forth or up and down. Harshness is
a ride quality issue where the vehicle's response to the road transmits sharply to the customer.
Harshness normally describes a firmer than usual response from the suspension system. Noise,
vibration and harshness (NVH) is a term used to describe these conditions, which result in varying
degrees of dissatisfaction. Although, a certain level of NVH caused by road and environmental
conditions is normal. This section is designed to aid in the diagnosis, testing and repair of NVH
concerns.
Acceptable Noise, Vibration and Harshness
All internal combustion engines and drivelines produce some noise and vibration; operating in a real
world environment adds noise that is not subject to control. Vibration isolators, mufflers and dampers
reduce these to acceptable levels. A driver who is unfamiliar with a vehicle can think that some sounds
are abnormal when actually the sounds are normal for the vehicle type. For example, Traction-
Lok®
differentials produce a slight noise on slow turns after extended highway driving. This is acceptable
and has no detrimental effect on the locking axle function. As a technician, it is very important to be
familiar with vehicle features and know how they relate to NVH concerns and their diagnosis. For
example, if the vehicle has automatic overdrive, it is important to test drive the vehicle both in and out
of overdrive mode.
Diagnostic Theory
The shortest route to an accurate diagnosis results from:
zsystem knowledge, including comparison with a known good system.
z system history, including repair history and usage patterns.
z condition history, especially any relationship to repairs or sudden change.
z knowledge of possible sources.
z using a systematic diagnostic method that divides the system into related areas.
The diagnosis and correction of noise, vibration and harshness concerns requires:
za road or system test to determine the exact nature of the concern.
z an analysis of the possible causes.
z testing to verify the cause.
z repairing any concerns found.
z a road test or system test to make sure the concern has been corrected or brought back to
within an acceptable range.
Glossary of Terms SECTION 100-
04: Noise, Vibration and Harshness 2003 Mustang Workshop Manual Klj . 1 ba
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Clonk
A hydraulic knocking sound. Sound occurs with air pockets in a hydraulic system. Also described as
hammering.
Clunk/Driveline Clunk
A heavy or dull, short-
duration, low-frequency sound. Occurs mostly on a vehicle that is accelerating or
decelerating abruptly. Also described as a thunk.
Coast/Deceleration
Releasing the accelerator pedal at cruise, allowing the engine to reduce vehicle speed without
applying the brakes.
Coast/Neutral Coast
Placing the transmission range selector in NEUTRAL (N) or depressing the clutch pedal while at
cruise.
Constant Velocity (CV) Joint
A joint used to absorb vibrations caused by driving power being transmitted at an angle.
Controlled Rear Suspension Height
The height at which a designated vehicle element must be when driveline angle measurements are
made.
Coupling Shaft
The shaft between the transfer case and the front drive axle or, in a two- piece rear driveshaft, the front
section.
CPS
Cycles per second. Same as hertz (Hz).
Cracks
A mid- frequency sound, related to squeak. Sound varies with temperature conditions.
Creak
A metallic squeak.
Cruise
Constant speed on level ground; neither accelerating nor decelerating.
Cycle
The process of a vibrating component going through a complete range of motion and returning to the Klj . 4 ba
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Lateral runout means measuring the movement or "wobble" of a wheel or tire at the sidewall. Radial
runout means measuring the out-of-
round at the tread surface.
Rustling
Intermittent sound of varying frequency (100- 2000 Hz), sounds similar to shuffling through leaves.
Shake
A low- frequency vibration (5-20 Hz), usually with visible component movement. Usually relates to tires,
wheels, brake drums or brake discs if it is vehicle speed sensitive, or engine if it is engine speed
sensitive. Also referred to as a shimmy or wobble.
Shimmy
An abnormal vibration or wobbling, felt as a side- to-side motion of the steering wheel in the driveshaft
rotation. Also described as waddle.
Shudder
A low- frequency vibration that is felt through the steering wheel or seat during light brake application.
Slap
A resonance from flat surfaces, such as safety belt webbing or door trim panels.
Slip Yoke/Slip Spline
The driveshaft coupling that allows length changes to occur while the suspension articulates and while
the driveshaft rotates.
Squeak
A high- pitched transient sound, similar to rubbing fingers against a clean window.
Squeal
A long- duration, high- pitched noise.
Static Balance
The equal distribution of weight around the wheel. Statically unbalanced wheel and tire assemblies can
cause a bouncing action called wheel tramp. This condition will eventually cause uneven tire wear.
Tap
A light, rhythmic, or intermittent hammering sound, similar to tapping a pencil on a table edge.
Thump
A dull beat caused by two items striking together. Tick Klj . 9 ba
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z
Did any abnormal occurrence coincide with or proceed its appearance?
Use the information gained from the customer to accurately begin the diagnostic process.
Pre- Drive Check
It is important to do a pre- drive check before road testing the vehicle. A pre- drive check verifies that
the vehicle is relatively safe to drive and eliminates any obvious faults on the vehicle.
The pre- drive check consists of a brief visual inspection. During this brief inspection, take note of
anything that will compromise safety during the road test and make those repairs/adjustments before
taking the vehicle on the road.
Preparing for the Road Test
Observe the following when preparing for the road test:
zReview the information recorded on the NVH Diagnostic Guide. It is important to know the
specific concern the customer has with the vehicle.
z Do not be misled by the reported location of the noise/vibration. The cause can actually be
some distance away.
z Remember that the vibrating source component (originator) may only generate a small
vibration. This small vibration can in turn cause a larger vibration/noise to emanate from another
receiving component (reactor), due to contact with other components (transfer path).
z Conduct the road test on a quiet street where it is safe to duplicate the vibration/noise. The ideal
testing route is an open, low- traffic area where it is possible to operate the vehicle at the speed
in which the condition occurs.
z If possible, lower the radio antenna in order to minimize turbulence. Identify anything that could
potentially make noise or be a source of wind noise. Inspect the vehicle for add- on items that
create vibration/noise. Turn off the radio and the heating and cooling system blower.
z The engine speed is an important factor in arriving at a final conclusion. Therefore, connect an
accurate tachometer to the engine, even if the vehicle has a tachometer. Use a tachometer that
has clearly defined increments of less than 50 rpm. This ensures an exact engine speed
reading.
Verify the Customer Concern
Verify the customer concern by carrying out a road test, an engine run- up test, or both.
The decision to carry out a road test, an engine run- up test, or both depends on the type of NVH
concern. A road test may be necessary if the symptom relates to the suspension system or is sensitive
to torque. A drive engine run- up (DERU) or a neutral engine run- up (NERU) test identifies noises and
vibrations relating to engine and drivetrain rpm. Remember, a condition will not always be identifiable
by carrying out these tests, however, they will eliminate many possibilities if carried out correctly.
Road Test Klj . 5 ba
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NOTE:
It may be necessary to have the customer ride along or drive the vehicle to point out the
concern. During the road test, take into consideration the customer's driving habits and the driving
conditions. The customer's concern just may be an acceptable operating condition for that vehicle.
The following is a brief overview of each test in the order in which it appears. A review of this
information helps to quickly identify the most appropriate process necessary to make a successful
diagnosis. After reviewing this information, select and carry out the appropriate test(s), proceeding to
the next step of this process.
zThe Slow Acceleration Test is normally the first test to carry out when identifying an NVH
concern, especially when a road test with the customer is not possible.
z The Heavy Acceleration Test helps to determine if the concern is torque- related.
z The Neutral Coast Down Speed Test helps to determine if the concern is vehicle speed- related.
z The Downshift Speed Test helps to determine if the concern is engine speed- related.
z The Steering Input Test helps to determine how the wheel bearings and other suspension
components contribute to a vehicle speed- related concern.
z The Brake Test helps to identify vibrations or noise that are brake related.
z The Road Test Over Bumps helps isolate a noise that occurs when driving over a rough or
bumpy surface.
z The Engine Run- Up Tests consist of the Neutral Run- Up Test and the Engine Load Test. These
tests help to determine if the concern is engine speed- related.
z The Neutral Run- Up Test is used as a follow- up test to the Downshift Speed Test when the
concern occurs at idle.
z The Engine Load Test helps to identify vibration/noise sensitive to engine load or torque. It also
helps to reproduce engine speed- related concerns that cannot be duplicated when carrying out
the Neutral Run- Up Test or the Neutral Coast Down Test.
z The Engine Accessory Test helps to locate faulty belts and accessories that cause engine
speed- related concerns.
z The Vehicle Cold Soak Procedure helps to identify concerns occurring during initial start- up and
when an extended time lapse occurs between vehicle usage.
Slow Acceleration Test
To carry out this test, proceed as follows:
zSlowly accelerate to the speed where the reported concern occurs. Note the vehicle speed, the
engine rpm and, if possible, determine the vibration frequency.
z Attempt to identify from what part of the vehicle the concern is coming.
z Attempt to identify the source of the concern.
z Proceed as necessary.
Heavy Acceleration Test
To carry out this test, proceed as follows:
zAccelerate hard from 0- 64 km/h (0-40 mph).
z Decelerate in a lower gear.
z The concern is torque related if duplicated while carrying out this test.
z Proceed as necessary. Klj . 6 ba
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Neutral Coast Down Speed Test
To carry out this test, proceed as follows:
zDrive at a higher rate of speed than where the concern occurred when carrying out the Slow
Acceleration Test.
z Place the transmission in NEUTRAL and coast down past the speed where the concern occurs.
z The concern is vehicle speed- related if duplicated while carrying out this test. This eliminates
the engine and the torque converter as sources.
z If the concern was not duplicated while carrying out this test, carry out the Downshift Speed
Test to verify if the concern is engine speed related.
z Proceed as necessary.
Downshift Speed Test
To carry out this test, proceed as follows:
zShift into a lower gear than the gear used when carrying out the Slow Acceleration Test.
z Drive at the engine rpm where the concern occurs.
z The concern is engine speed related if duplicated while carrying out this test. This eliminates the
tires, wheels, brakes and the suspension components as sources.
z If necessary, repeat this test using other gears and NEUTRAL to verify the results.
z Proceed as necessary.
Steering Input Test
To carry out this test, proceed as follows:
zDrive at the speed where the concern occurs, while making sweeping turns in both directions.
z If the concern goes away or gets worse, the wheel bearings, hubs, U- joints (contained in the
axles of 4WD applications), and tire tread wear are all possible sources.
z Proceed as necessary.
Brake Test
To carry out this test, proceed as follows:
zWarm the brakes by slowing the vehicle a few times from 80–32 km/h (50–20 mph) using light
braking applications. At highway speeds of 89–97 km/h (50– 60 mph), apply the brake using a
light pedal force.
z Accelerate to 89–97 km/h (55–60 mph).
z Lightly apply the brakes and slow the vehicle to 30 km/h (20 mph).
z A brake vibration noise can be felt in the steering wheel, seat or brake pedal. A brake noise can
be heard upon brake application and diminish when the brake is released.
Road Test Over Bumps
To carry out this test, proceed as follows: Klj . 7 ba
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NOTE:
A serpentine drive belt decreases the usefulness of this test. In these cases, use a
vibration analyzer, such as the VA, to pinpoint accessory vibrations. An electronic listening
device, such as an EngineEAR, will also help to identify noises from specific accessories.
Remove the accessory drive belts.
z Increase the engine rpm to where the concern occurs.
z If the vibration/noise is duplicated when carrying out this test, the belts and accessories are not
sources.
z If the vibration/noise was not duplicated when carrying out this test, install each accessory belt,
one at a time, to locate the source.
Vehicle Cold Soak Procedure
To carry out this procedure, proceed as follows:
zTest preparations include matching customer conditions (if known). If not known, document the
test conditions: gear selection and engine rpm. Monitor the vibration/noise duration with a watch
for up to three minutes.
z Park the vehicle where testing will occur. The vehicle must remain at or below the concern
temperature (if known) for 6- 8 hours.
z Before starting the engine, conduct a visual inspection under the hood.
z Turn the key on, but do not start the engine. Listen for the fuel pump, anti- lock brake system
(ABS) and air suspension system noises.
z Start the engine.
z CAUTION: Never probe moving parts.
Isolate the vibration/noise by carefully listening. Move around the vehicle while listening to find
the general location of the vibration/noise. Then, search for a more precise location by using a
stethoscope or EngineEAR.
z GO to Symptom Chart — Idle Noise/Vibration to assist with the diagnosis.
6: Check OASIS/TSBs/Repair History
After verifying the customer concern, check for OASIS reports, TSBs and the vehicle repair history for
related concerns. If information relating to a diagnosis/repair is found, carry out the procedure(s)
specified in that information.
If no information is available from these sources, carry out the vehicle preliminary inspection to
eliminate any obvious faults.
7: Diagnostic Procedure
Qualifying the concern by the particular sensation present can help narrow down the concern. Always
use the "symptom" to "system" to "component" to "cause" diagnosis technique. This diagnostic method
divides the problem into related areas to correct the customer concern.
zVerify the "symptom".
z Determine which "system(s)" can cause the "symptom".
„If a vibration concern is vehicle speed related, the tire and wheel rpm/frequency or
driveshaft frequency should be calculated.
„ If a vibration concern is engine speed related, the engine, engine accessory or engine
firing frequencies should be calculated. Klj . 9 ba
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