Lending you our ear

Noise

I love noises and cars, so I drive as many as I can. The brain and its ability to recall information is amazing. Once you hear the same type of car noise three or four times, it gets registered in a database deep inside your head. Pretty soon you begin to recognize a familiar noise from a car as it drives by on the street. Suddenly you will find yourself standing on a sidewalk, mumbling “lower ball joint.”

A good noise technician uses a combination of logic, common sense and experience. As Overland Park’s “go-to source for auto repair,” our New Concept techs have all three! Logic comes into play when you have to diagnose the noise by process of elimination. Common sense is required when you begin to over think the noise. Experience comes from driving lots of different cars under different conditions.

We also have a secret weapon–an electronic device called a Mechanics Ear that does an incredible job locating the source of various car noises. The device consists of a transmitter, a wireless receiver and a set of earphones. There are four numbered transmitters that clip onto anything using a strong spring. The receiver comes with four numbered buttons (channels with different frequencies) matching the transmitters so you can listen to them, one at a time, and correlate their position. There is also a volume knob. We mainly use the Mechanics Ear to diagnose drivetrain, suspension and brake-type noises, or situations where the car needs to be in motion or going over bumps to reproduce the noise.

The most common area where we use this device is for wheel bearing-type noises, which can be very deceiving. Front wheel bearings go bad more often than rear ones; since the engine adds weight, the wheels are turning left to right and the front wheel is the first thing to hit a pothole. We simply clip a transmitter to something solid like the spindle at each corner of the car and go for a drive. With the sound amplified, it is usually pretty obvious which one is the culprit. Wheel bearings get loose as they wear and you can hear the subtle change in humming as you lightly swerve from side to side. After replacement we verify the noise is gone on the same test drive route.

Diagnosing suspension squeaks is also a good use for the Mechanics Ear. Many times a car will squawk when the suspension goes over bumps. These noises can come from ball joints, sway bar end links and/or frame mount bushings. Simply clip the transmitters to various points, go for a drive, and voila! In some cases we will disconnect the sway bar links from the car to see if the noise goes away. You can also spray a little temporary lubricant onto to a suspect frame mount bushing to determine the source.

Differentials are where the axles, various bearings, and ring and pinion gears are housed. Many times a howling noise from the rear of a pickup will be inside the differential, but very hard to pinpoint. Mounting the transmitters on both ends near the wheels and again in the center where the ring and pinion are located, will tell you which axle to focus on. If you get a humming noise when your SUV or truck is put into 4×4, then once again, we can quickly determine whether to investigate the transfer case or the front differential.

Brake squeaks are always an annoyance and usually occur because something is moving back and forth rapidly, and there is no lubricant where it should be.

Warped brake rotors often cause this movement even if you cannot feel it when stopping. Our technicians either take the brake system apart and start measuring every part at each corner of the car, or use the Mechanics Ear to find the location and inspect there. The device is so sensitive; you can even hear the brake pads touching the rotors when you apply the brakes. You can hear clicking noises coming from cracks or hot spots in rotors. Once I heard a dull tapping noise and found nothing wrong with the brakes, but finally noticed a nail in the tire with a big head on it. What a triumphant diagnosing moment that was!

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Noise Diagnosis
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