How to Diagnose Car Trouble with a Bird Sound

by Chris Stevenson
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Girl repair car on road image by Vasyl Dudenko from

Our vehicles communicate to us through a range of noises and sound frequencies when they need attention. A well-performing engine emits a smooth, constant hum in all driving conditions. However, if you listen closely, sometimes our engines can begin to complain by whining, howling and screaming. Some sounds can be less intimidating, like the swish, squeak or chirp-like bird sound. Each sound has its distinct origin and reason for calling attention to itself. With a good ear and some detective skills, the vehicle owner can narrow down some problem areas by interpreting sounds and noises.

Step 1

Drive your vehicle through an alleyway that has tall walls or buildings on both sides. Sounds will be amplified in such an area. Make sure all windows remain down for the test. Write down any unusual sound or noise you hear coming from the vicinity of the engine or suspension. Randomly accelerate and let off the pedal numerous times. Turn on all the accessories to load the alternator and make note of noises.

Step 2

Notice whether the noises disappear when you shut the accessories off. If you hear squeaks, chirps or squeals, you will have narrowed down the possible problem areas. Notice if the noise appears while driving the vehicle or during idle only. Idle only noises will rule out all suspension and wheel faults, confining the problem area to the engine, accessories, belts and vacuum hoses. Park the vehicle in a convenient location and let the engine run.

Step 3

Raise the hood and locate all the vacuum lines that run into the carburetor (or throttle body) and the intake manifold. If you hear a chirping noise, gently wiggle the vacuum hoses at their connection points and note any difference. A sucking vacuum leak can cause an intermittent chirp. Check the PCV (positive crankcase ventilation) vacuum hose for proper fitting and tightness at both ends (refer to owner's repair manual for location). Make sure the large black vacuum hose that enters the brake power booster has a tight seal at the grommet location.

Step 4

Check the power steering pump by sitting in the vehicle and turning the steering wheel to the full left and right stop position. A chirp, combined with a vibration or shudder in the steering wheel will denote a low power steering fluid level, or contaminated fluid in the power steering reservoir. Place the probe of an automotive stethoscope over the engine top and sides and listen for any chirp or squawk. Normally, internal engine noises will sound like clicks, knocks and metallic pounding. Rule them out.

Step 5

Fill a spray bottle with water. With the engine running, turn on the air conditioning unit at the dash panel to its maximum output. Turn on the headlights. Carefully spray water on the belts and pulleys at the front of the engine, if it has a multiple belt configurations. Spray water on the inside of the serpentine belt, if so configured. If the chirping noise temporarily disappears, you most likely have a loose, cracked or glazed belt.

Step 6

Shut the engine off and check the tightness and condition of all the belts. If the underside surface of a serpentine belt, or single accessory belt, shows a shiny glaze, it must be replaced.

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