Cars: What Noise Is a Bad Noise?

Cars are intrinsically noisy things. When you have tonnes of metal, hundreds of moving parts, and various liquids all compacted into one mechanical machine, it’s little wonder your vehicle will be emanating a few sounds. However, it’s important that you can distinguish the everyday sounds of a well-functioning vehicle from those that might be signs of trouble.

We spoke to VW Motor Parts, who specialise in Volkswagen parts, who said: “It’s vital that you learn to listen to the sounds of your car so that you get to know what’s normal and what’s not, to ensure you stay safe.

“Recognising bad noises as soon as possible and performing early maintenance can not only save you money, but might even save your life if any components become a danger.”

Here, we’ve found a few of the most common noises to help you recognise which ones might cause you problems with your car.

Noise when turning your steering wheel

If there is any sound that occurs when turning your steering wheel, whether it’s a crunch, a whine, or a creak, this is something that should not be ignored, as a problem with steering could pose a real danger.

Stemming from the steering system, it could come from the steering pump, rack, or belt, and will usually indicate that some component of the steering linkage needs lubricating or replacing.


If there is any clunking that occurs when braking, this could be a sign that a brake caliper or other component is damaged, missing, or incorrectly fitted. Similarly, if this clunking turns into a squealing or a grinding when applying the brakes, it’s usually a sign of worn-out brake pads.

Alternatively, if you hear a clunking noise when driving over speed bumps or across potholes, this could be a sign of worn shock absorbers.


A flapping noise is generally related to the fan or a belt within the vehicle. This could be as simple as something interfering with the fan, a belt that has become loose, or something more problematical like a worn-out belt.


This is usually quite a noticeable noise that comes when changing gears in a manual car and is indicative of an issue with the clutch.

It could suggest that the clutch is either worn or needs adjusting, or can be a sign of a deeper problem with the transmission, so it’s important to get it checked out as early as possible.


This will normally come from under the bonnet when the engine is first turned off, and is a sign of a number of problems.

It could be that something is leaking, like coolant or oil, which is then falling onto a hot part of the engine and producing a hissing sound. Alternatively, the vacuum line could be leaking, or even the engine could be overheating.


A knocking sound coming from the engine compartment is a common noise that usually stems from using a lower-grade fuel. This is easily rectified by draining the petrol out of your car and following the owner’s manual requirements for oil and petrol.

A loud bang

This is difficult to go unnoticed as it sounds like something has just exploded in your car! A loud bang occurs when a car backfires and could indicate two main problems.

Firstly, a backfire could suggest that the air-fuel mixture is too rich. Alternatively, it could indicate a deeper problem, in that the catalytic converter isn’t functioning properly.


This is sometimes quite hard to distinguish from the usual hum of the engine and usually requires an expert ear to identify the issue, but if it sounds as if it’s coming from under the car, then it’s usually a problem.

It can be the sign of the transmission failing, the differential needing lubricating, the wearing of the universal joints, or even a worn-out wheel bearing.

If you’re still unsure what noise your car is making, this handy website has a whole host of recorded sounds and their related problems to help you identify any issues. And, to make it easier to discuss your problems with your mechanic, the Chicago Tribune has created an automotive glossary.