You know how your car normally behaves. When a new noise appears, you immediately notice that something has changed, even if you do not know the exact mechanical term.
“It clicks”, “it squeals” or “it hums” are useful descriptions, but two people may use the same word for completely different sounds. The circumstances in which the noise occurs are often more informative than the name given to it.
Is an unusual noise always serious?
No. Some noises are temporary or related to a situation that is not immediately serious. Others indicate wear or a fault that may worsen. It is impossible to distinguish between them remotely without inspecting the vehicle.
To assess the priority, ask yourself:
- did the noise appear suddenly or gradually?
- is it becoming louder or more frequent?
- is it related to engine speed or vehicle speed?
- does it occur when braking, accelerating, turning or driving over bumps?
- is it accompanied by a warning light, vibration, smell or loss of performance?
- have the steering, braking or road-holding characteristics changed?
A quiet, stable noise with no other symptoms does not have the same urgency as a sudden metallic impact accompanied by severe vibration. In every case, avoid postponing the inspection indefinitely.
When should you stop driving because of a noise?
Stop as soon as it is safe to do so and seek advice if the noise is accompanied by:
- reduced braking performance or a significant change in braking;
- heavy or imprecise steering, or unusual play;
- severe vibration through the steering wheel, body or a wheel;
- a red warning light, overheating or an oil-pressure warning;
- smoke, a burning smell or a significant leak;
- a part rubbing, dragging beneath the vehicle or touching a wheel;
- a loud engine knock that rapidly becomes worse;
- a sudden loss of power or very uneven running.
Why does the car make a noise when starting?
A noise heard only while the engine is cranking may direct the investigation towards the starter motor, its drive mechanism, the battery or the engine beginning to turn. A sound that appears just after a cold start may also involve the auxiliary belt, a pulley, a driven component or lubrication.
Note precisely:
- whether the engine is cold, warm or being restarted after a short stop;
- whether the noise occurs before, during or after starting;
- whether it lasts for one second, several seconds or remains constant;
- whether it changes as engine speed increases;
- whether a warning light remains on or the engine is difficult to start.
These examples provide clues, not a diagnosis. A belt, a pulley and an internal problem may produce sounds that a driver describes in a similar way.
What does a noise while driving mean?
When a noise occurs only while the vehicle is moving, it may come from a component that rotates with the wheels or operates under load: a tyre, bearing, brake, transmission, driveshaft, exhaust or another component.
The noise increases with vehicle speed
If the frequency of the noise follows vehicle speed, even when you release the accelerator, a component related to the wheels, tyres or transmission may be involved. Also note whether the sound changes when taking a gentle bend.
The noise follows engine speed
If the noise changes while stationary as engine speed varies, the investigation is more likely to focus on the engine, its auxiliary components, the intake or the exhaust. This distinction is useful, but it is not enough to identify the cause.
The noise occurs only when accelerating
A noise under load may involve the engine, transmission, a mounting, the exhaust or an air leak. Note the selected gear, engine speed, engine temperature and how hard you were accelerating when the noise appeared.
Why does the car make a noise when turning the steering wheel?
Repeated clicking while cornering, rumbling, creaking at low speed or whining while steering may have different causes: the transmission, steering, a wheel, bearing, spring, suspension or power-steering system.
Observe whether the noise occurs while stationary or only while driving, whether it is louder on one side, whether it depends on the steering angle and whether it is accompanied by stiffness, unusual steering-wheel return or vibration.
Why does the car squeal or scrape when braking?
A noise when braking may have several causes: moisture or a surface deposit, a wear indicator, brake pads, discs, a protective component, a foreign object or another fault. The sound alone cannot determine whether the brakes are still safe.
Have the vehicle inspected promptly if the noise is accompanied by:
- a soft or very hard pedal, or one that travels unusually far;
- significant vibration through the pedal or steering wheel;
- a braking distance that appears to be increasing;
- the vehicle pulling to one side under braking;
- a continuous metallic noise or a burning smell;
- a brake warning light.
Braking directly affects safety. A new or significant noise therefore deserves an inspection, even if the car still appears to slow down.
Why does a knocking noise occur over bumps?
A knocking noise over speed bumps, cobblestones or uneven roads may come from the suspension, a bush, link rod, mounting, spring, braking component, exhaust or even an unsecured object in the boot.
With the vehicle stationary, begin by checking that the spare wheel, jack, tools and transported items are properly secured. Never go underneath a vehicle supported only by a jack.
If the noise is accompanied by excessive bouncing, an uneven ride height, a rubbing tyre or unusual road holding, a mechanical inspection is necessary.
How can you describe the noise effectively to a professional?
You do not need to guess which part is responsible. Describe what you notice using simple reference points:
When it happens
When cold, when warm, while starting, accelerating, braking, turning or driving over a bump.
Its rhythm
Continuous, intermittent, regular, related to vehicle speed or engine speed.
The area
Front, rear, left, right, engine, underneath the vehicle or near a wheel.
Other signs
A warning light, vibration, smell, leak, loss of power, or changed steering or braking.
An audio or video recording may be useful if it is made safely by a passenger or while the vehicle is stationary. Never use your phone while driving, and do not position yourself near a moving component to record the sound.
How does Depamec investigate an unusual noise in Geneva?
Depamec can carry out an initial inspection at the vehicle's location when conditions allow. The visit begins by reviewing the circumstances in which the noise appeared, the vehicle's recent history and any other symptoms observed.
Depending on the noise, the technician may carry out a visual inspection, check fluid levels, look for play, inspect the wheels, brakes, suspension or engine compartment, and read electronic faults when this provides useful information.
Some noises cannot be confirmed while stationary. A road test, vehicle lift, dismantling or workshop equipment may then be necessary. This step is explained before a repair or the replacement of a part is proposed.
Frequently asked questions about car noises
Does an unusual noise mean the car is unsafe?
Not necessarily, but a new noise should not be ignored. Its severity depends on when it occurs, how it develops and any associated symptoms such as vibrations, a warning light, reduced braking performance or a steering problem.
When should you stop because of a noise?
Stop as soon as it is safe to do so if the noise is accompanied by reduced braking or steering, severe vibration, smoke, a burning smell, overheating, a red warning light or a significant leak.
Why does my car make a noise when I brake?
There are several possible causes, from surface deposits to wear or a fault in a braking component. A metallic noise, an unusual pedal, vibrations or reduced braking performance require a prompt inspection.
Why does the noise increase with speed?
A noise that follows vehicle speed may come from a rotating component such as a tyre, wheel, bearing or the transmission, but only an inspection can identify the cause.
Is an audio recording enough to diagnose the noise?
No. A recording can help explain the symptom, but it does not replace examining the vehicle, reproducing the noise and carrying out mechanical checks.
Can a car noise be diagnosed at home in Geneva?
In some situations, yes. Depamec can carry out an initial inspection at the vehicle's location. However, some noises require a road test, a vehicle lift or workshop equipment.