When driving a vehicle a slight amount of whistling is normal due to the airflow traveling over the body, windows and roof, but when sound levels increase it can tell you there is a problem.
Whistling noises can be generated by the engine, alternator or window and door seals that have an issue such as deteriorating rubber or corrosion on the battery cables forcing the alternator to overwork itself, or the alternator itself is going out.
These kinds of repairs are two stages, first the source of the whistling sound must be located, followed by the repair of the problem. A shop or dealer will charge an hourly rate for both aspects of the repair.
Vacuum is present when the engine is running and is at its strongest point when
the engine is idling. This will generate various whistling noise pitches as the
engine changes rotational speed. Lift
the hood to inspect the engine vacuum line routing hoses to the different accessories
such as the brake booster and
Repair the vacuum leak
The alternator is designed
to recharge the battery and keep electrical power supplied to the vehicle when
in operation. If the alternator is starting to go out or if it is being overworked
by high resistance caused by
dirty battery cables
or a bad battery it can create
whistling noise. To repair this issue start by
cleaning the cables
and checking the battery. If everything
checks out, replace the alternator.
When a door or window seal fails it can create a whistling noise as air enters
and passes through the passenger compartment, it helps to have someone in the car
with you to help find the origin of the noise, inspect the door or window seal in
that area and replace or repair as needed.
A window seal has a top, bottom, front and rear sealing points, while traveling
and the noise is being generated use your fingers against the seal to try and stop
the noise this will let you know the location of the defect. In most cases the window
seal will need to be replaced.
Windshields and sunroofs can also whistle when the seals have failed. Hood ornaments or other accessories on the exterior of the vehicle can whistle as well. We had a customer that change their antenna to one that had the mast bent into the shape of a horse, and it whistled. For window leaks a great trick is to turn the blower motor on high (non recirculation) and then go around the outside of the doors/windows with something like a smoke machine, incense stick or even a candle flame and watch for movement of the smoke or flame to show the leak location.
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