News & Insights

Heard something go bump on the road? Your vehicle may be trying to tell you something

Classic cars, everyday cars, vans and motorbikes all develop their own familiar sounds.

You get used to the engine note, the odd creak from the cabin and the small mechanical noises that come with regular use.

So when something new appears, it tends to stand out.

A clunk when you pull away, a knock over a bump or a rumble that gets louder with speed can all be signs that something has changed.

The important thing is not to diagnose the problem from the noise alone.

The same sound can have several possible causes, which is why it helps to notice exactly when it happens and whether anything else feels different at the same time.

A valid MOT certificate also does not guarantee that a vehicle will remain safe and roadworthy until its next test.

If a new noise appears and you cannot explain it, it is worth getting it checked.

A clunk when changing gear or pulling away

A heavy clunk when you engage a gear or move off can immediately make you think of the gearbox.

That is only one possibility.

Worn engine or gearbox mounts can allow extra movement when power is applied, while the clutch or transmission may also need attention.

Try to notice the pattern.

Does it happen every time you pull away? Only in certain gears? Does it occur when you lift off the accelerator?

If you also notice juddering, difficulty selecting gears or a change in the way the vehicle drives, mention that when you speak to the garage.

The noise itself does not confirm the cause, but those extra details can help a mechanic narrow things down.

A knock over speed bumps or potholes

If a knock appears mainly on uneven roads, the suspension is one area a mechanic may inspect.

Worn suspension parts or a damaged spring can create clunks and rattles.

A loose exhaust can make a similar sound, which is why noises from underneath the vehicle are not always easy to identify from the driver’s seat.

If the vehicle is a van, note whether the sound changes when it is carrying a load.

That may help the garage reproduce the fault, but it does not necessarily mean the load itself is the cause.

A metallic rattle from underneath

A rattle beneath the vehicle often sounds as though something is loose.

Sometimes that is exactly what is happening.

An exhaust component or another part may be vibrating against the underside of the vehicle.

The AA also notes that a failing catalytic converter can make a noise similar to a loose exhaust.

Sound can travel through the body of a car, so what seems to come from one place may actually be coming from somewhere else.

A proper inspection is the best way to identify the source.

A rumble that gets louder with speed

A wheel bearing problem may not sound like a knock at all.

It can present as a hum or rumble that becomes more noticeable as road speed increases.

Tyres and other wheel-related faults can also create unfamiliar noises.

If the sound changes with speed, tell the garage.

That pattern can be more useful than trying to guess which component is faulty.

Scraping, clicking or grinding when braking

New noises during braking should be taken seriously.

Scraping, clicking or grinding could be caused by worn brake components or something caught near a brake disc.

If a vehicle has been standing for a while, surface rust on the discs can also sometimes cause temporary noise.

A knock when turning may point towards steering or suspension parts instead.

Because braking, steering and suspension all affect the way the vehicle handles, changes in these areas should be checked promptly.

If the noise is severe, or braking and handling feel different, stop somewhere safe and seek professional advice before continuing.

What about classic cars?

Older vehicles can naturally have more mechanical character than modern ones.

That does not mean every new noise should simply be accepted as part of classic-car ownership.

A classic may have more noticeable drivetrain, suspension or exhaust sounds, but you are still looking for a change from what is normal for that particular vehicle.

If a familiar sound becomes louder, changes character or is joined by vibration, pulling, juddering or difficulty selecting gears, it is worth having the car inspected.

Knowing your own vehicle is useful.

Assuming every noise is just “one of its quirks” is less helpful.

And what about motorbikes?

Motorbike noises deserve the same care.

Changes can sometimes be easier to feel as well as hear.

Pay attention to whether a sound appears over bumps, during braking or when applying power.

The chain and sprockets, suspension, wheel bearings and exhaust are all areas a mechanic may need to inspect.

An excessively loose or worn chain or sprocket can be treated as a serious MOT defect.

If the bike feels different under braking, steering or acceleration, do not rely on the noise alone to tell you what is wrong.

Have it checked.

What should you tell the garage?

Before booking the vehicle in, make a quick note of what you have noticed.

Useful details include:

• when the noise happens

• whether it changes with road speed

• whether it occurs during braking, steering or gear changes

• where it seems to come from

• whether it is becoming louder or more frequent

• whether the vehicle feels different to drive

That information can help a mechanic reproduce the problem and trace the cause more quickly.

Only an inspection can confirm what is actually wrong and whether the vehicle is safe to use.

So, if your car starts going bump on the road this Halloween, there is probably a mechanical explanation rather than anything supernatural.

Still, if your classic suddenly develops a new rattle, knock or groan all on its own, it may be worth listening to what it is trying to tell you.

Happy Halloween!