Unusual car noises explained

Common car noises and what they mean

Most unusual car noises could have one of several causes, depending on where they’re coming from, and what action you’re performing at the time. We’ll get into those specifics in the next section, but here’s a general overview of common car sounds and their potential causes:

• Squealing - Worn brake pads or fan belt, or low power steering fluid.

• Grinding - Worn brake pads, alternator, clutch, or wheel bearings, a damaged water pump, or gearbox problems.

• Clicking - Low oil level, a faulty starter motor, or a worn or damaged constant velocity (CV) axle.

• Knocking - Wrong fuel, worn bearings, or connection rods - or uneven air/fuel mixture.

• Hissing - Exhaust, vacuum or coolant leaks, or a damaged air conditioning valve/hose.

• Rattling - Loose exhaust system parts, a broken catalytic converter, misaligned wheels, or suspension problems.

• Humming - Worn CV axle or wheel bearings, or a faulty gearbox.

• Flapping - Broken fan belt or flat tyres.

• Rumbling - An exhaust leak or wheel bearing issue.

• Whining - Low power steering fluid, low engine oil level, a stuck valve, or gearbox problems.

Where is my car noise coming from?

When you’re trying to figure out where those unusual car noises are coming from, there are a few tricks you can employ:

First, try driving with the windows open; this can help you hear things more clearly and pinpoint where the sounds are coming from. Once you close the windows, you can tell if the noise is occurring inside or outside, which narrows things down a bit.

You can also ask a friend to stand outside the car while you start it up. They can catch sounds you might miss from the driver’s seat. However you approach it, identifying where an unusual car noise is coming from can be extremely helpful when it comes to diagnosing its cause.

Noises from the engine

• If you hear a hissing or sizzling noise from your engine, this could be a sign that it’s overheating, usually because the radiator is leaking, or fluid is dripping onto hot engine parts.
• If you notice clicking or ticking sounds, that might mean you’re running low on oil - or that your spark plugs or valves are misaligned.
• A knocking or pinging sound can indicate you’ve used the wrong fuel - or it could point to worn bearings, a loose cambelt, carbon build-up, or an uneven air/fuel mix.
• If there’s rattling or shaking coming from under the bonnet, it’s likely that some parts are loose or that your belt is worn out.
• Any whining usually means you're low on engine oil or your valves are stuck.

Noises from the wheels

• A squeaking or squealing noise from one or more of the wheels when braking usually means the brake pads are on their last legs and need replacing.
• If you start hearing grinding sounds when you hit the brakes, that’s a sure sign that the brake pads have completely worn down - and your brake discs are in danger of damage.
• A clunking or knocking sound when you drive over bumps often means there’s a problem with your suspension, such as worn-out shock absorbers.
• A thumping or flapping sound usually indicates a flat or worn tyre.
• Rattling could mean your wheels are misaligned.
• A humming or rumbling sound can mean your wheel bearings are failing.

Noises from under the car

• If you hear a clunking noise underneath your car (especially from the front), this could mean that parts of your suspension are damaged or wearing out (e.g. shock absorbers, ball joints, or even control arm bushes).
• A rhythmic thudding is likely to mean your driveshaft has become unbalanced.
• Grinding noises at the rear of the underside sometimes indicate trouble with the differential.
• Rattling could mean there are loose parts in the exhaust, such as the heat shields, silencer, or exhaust pipe.
• Any squeaking sounds could be down to the suspension, particularly the shock absorbers - and worn-out CV axles.

If you hear any of these strange sounds, you should get your car checked immediately. Otherwise, an easy fix could develop into a major problem needing costly repairs.

It’s important to be as precise as possible when describing any unusual car noises to a mechanic. Clarify where the noise is coming from, when it occurs, how loud it is, whether it started suddenly or developed gradually - and how long it’s been present.

If the noise comes from inside or occurs when the car is stationary, you might even be able to record it on your phone, which will help the mechanic identify it.

When should I go to the mechanic?

Simple maintenance tasks such as topping up fluids, checking tyre pressure, and replacing spark plugs can go a long way towards fixing certain unusual car noises. Routinely taking your car to a trusted local garage for check-ups can prevent them starting altogether.

However, if you notice a concerning sound between check-ups, you should visit your mechanic promptly. Bear in mind that some sounds warrant more urgent action than others.

If you hear light squeaks from the brakes when you first use them, quiet ticks from the engine when you start up in the cold, or rattling from the interior of the car, this is worth investigating, but there’s no need to drop everything and visit a garage immediately.

On the other hand, knocking, banging, grinding, whining, or hissing sounds can be indicative of more serious problems. So, it’s best to visit your mechanic as soon as you hear them. Otherwise, there’s a real risk these issues will escalate, landing you with a hefty repair bill.

Getting your car ready to sell

A quiet car will usually have a higher resale value than one that’s banging, thumping, and squeaking along the road.

Therefore, addressing any concerning sounds before you sell your car could help you make more cash. In many cases, a few well-placed fixes can help a creaky car run like a dream.

However, unusual car sounds can sometimes be caused by severe issues that are simply too expensive to fix. If you have an older car, the cost of these repairs may even exceed its current resale value.

Before investing in significant repairs, it’s worth checking what your car is currently worth. You can use our free car valuation tool to get a quote in under 30 seconds. This will give you a clear indication of whether it’s best to repair or sell your car.

Severe mechanical issues can make it more difficult to find a private buyer. However, webuyanycar offers a convenient car buying service with a guaranteed sale. We can buy your old car regardless of its age and condition, making the selling process simpler and easier.