Troubleshooting Guide

NOTE: A "rattle," "clunk," "pop," "squeak," "creak" or "crunch" noise may be heard from the front underbody. Use the following diagnostic procedure along with the list of common sources of noise and recommended repair procedures to determine where the concern is and how to correct it.

STEP 1: INTERVIEW CUSTOMER
Understand the customer's description of the noise.
^ Road test the vehicle with the customer to fully understand where, how and when the noise occurs.
^ Is the noise speed dependent? Road surface dependent? or Temperature/weather dependent?

STEP 2: DUPLICATE NOISE CONCERN
Is the noise heard while bouncing the bumper of the vehicle?
^ Or, is the noise heard while driving over rough road surface?
^ Or, is the noise only heard while driving while braking?
^ Or, is the noise heard while turning (while driving, or while parked)?

NOTE: Typically, front underbody noise is heard while bouncing the bumper of the vehicle. If the noise can not be duplicated during the static bounce, or during low speed turning maneuvers, it most likely is not suspension related.

STEP 3: ISOLATE NOISE CONCERN
^ If the noise can be duplicated by pushing up and down on the vehicle while stationary. Use a stethoscope or chassis ears to determine the area of the chassis that the noise appears to be coming from.
^ Another method of isolating a noise is to place your hand on the coils spring, radius arm, or stabilizer bar while someone pushes up and down on the vehicle. This will allow you to feel the vibrations.

NOTE: This method is sometimes misleading as the vibrations may carry from one suspension component to another.

^ Spray a liberal amount of penetrating oil on the suspension components which appear to be creating the noise. If the noise stops after lubrication, refer to the appropriate component for repair.

STEP 4: INSPECT VEHICLE
Loose fasteners
^ Worn/broken parts
^ Excessive dirt/rust accumulation

STEP 5: SERVICE VEHICLE
Service the vehicle in accordance with the repair procedures outlined in this manual.

STEP 6: TEST DRIVE VEHICLE
Drive the vehicle over the same road surface on which the customer demonstrated the noise, to verify that it was correctly identified and repaired.

STEP 7: FOLLOW-UP WITH CUSTOMER
Follow-up with the customer about two weeks after service is performed to ensure the noise was correctly identified and repaired.





DESCRIPTION OF UNDERBODY NOISES
The following noises may be heard from the front underbody during normal driving conditions. A brief description of each noise is included to provide consistency during the diagnostic and repair procedures.

Rattle
A continuous light metallic noise induced by driving over rough road surfaces (i.e., tar strips, bumps, patched surface). A sound suggesting looseness, such as marbles rolling around in vehicle.

Clunk
A heavy metallic noise heard upon impact of bumps. Typically, a "clunk" is heard once upon each impact.

Pop
It is similar to a "clunk", but a lighter sound. It is heard upon impact of rough road surfaces, or during braking. Typically, a pop is heard once upon each impact or brake application.

Squeak
A high pitch sound, like rubbing a clean window, heard during suspension movement (jounce or rebound). A suspension squeak may be induced by driving over undulating surfaces, or while bouncing a stationary vehicle.

Creak
A creak is similar to a squeak, but usually louder, produced by a metal-to-metal, or rubber to metal rubbing motion which may occur during suspension movement (jounce or rebound).