How to Find Squeaks and Rattles - Chassis Ears

Image How to Find Squeaks and Rattles - Chassis Ears
By Dennis Bandy Copyright  

Finding squeaks and rattles in a vehicle's steering, suspension or uni-body can be very time consuming. Before using a listening device like chassis ears, determine the general location of the noise and under what conditions the noise occurs. Sometimes customers will have many noises coming from their vehicles. Somehow they can block them all out except the most recent noise that has popped up. Unless the service writer has went for a test drive with the customer, verified the specific noise and noted under what conditions the noise is heard, the job can be even harder. If the customer is still there, a five minute test drive with them could save a lot of time chasing the wrong noise. Many times the customer won't even be able to duplicate the noise. The technician that takes the customer seriously will more than likely have a repeat customer. I wish I had a nickel for every test drive, that a customer has said "I know you think I'm crazy, but I did hear a noise". If the noise cannot be duplicated, more than a quick safety inspection may be a waste of time. After-all it's hard to find ghosts and gremlins when they choose to be silent. The customer may choose to leave the car so it can be driven when it has had time to cool off, since some noises are only present under certain conditions. Be sure to have the customer describe the noise to you, since the translation by the service writer can vary. Some noises can be described easily. Once a customer described the noise her car was making as "it squeaks like bed springs".

A simple mechanic's stethoscope is a useful tool but it does have limitations. The stethoscope cannot be used while the car is being driven in the parking lot or down the road. A specialty tool that can be used while the vehicle is moving, is the is the STE6600 wired chassis ears. It has six microphones with clips and wires that can be attached to various components in the vicinity of the noise. By listening with the headphones and turning the selector to isolate each of the microphones one by one. The channel that picks up the most noise is noted by color code to help pinpoint the source of the noise. One drawback with this design is having to route the wires through the window, under the vehicle, around exhaust and moving parts of the drive-train. The chance of damaging the wires with this model is high and the set up time to prevent damage to the wires can be discouraging.

The STE97202 wireless chassis ears has four numbered wireless microphones, there is reduced set up time and less chance of damaging the listening device components. Care still needs to be taken with either set of chassis ears. It is necessary for safety, to have someone else driving the car to duplicate the noise while the technician monitors the chassis ears.



Additional Tips

1. Look for rust stains that may indicate worn bushings or loose bolts or components. The metal sleeve of a bushing needs to be stationary, if it moves it will be noisy.

2. Look for TSB's (Technical Service Bulletins) that may have been issued by the car manufacturer. Sometimes additional spot welds are required to the uni-body or updated parts are designed to remedy a noise.

3. Look for signs of a previous impact. Mis-aligned or damaged uni-bodies may be the source of creaking noises, especially if the vehicle has been involved in an accident.

4. Check the torque on every bolt possible, find a loose one and fix may be easy. Suspension and steering bolts are the obvious ones to check. I once found loose bolts on a panel behind the rear seat back. The panel went between the rear strut towers. The bolts were slightly loose, but created a noise on turns that several shops could not find.

5. Check for loose articles. "Loose articles" could include a jack in the trunk, a car battery causing a thump on an abrupt stop, a pair of sunglasses rattling in the console.

With common sense, a logical approach and using the right tools, finding noises and performing related repairs can increase profits and customer loyalty.
Finding squeaks and rattles in cars can be very time consuming, but fixing and repairing these noises quickly can earn customer loyalty.