Name that Tune? How to Diagnose Faults from Car Noises

It’s time for us to take a look at the sonic symptoms of various car issues, particularly when braking, cornering or even putting your foot down and accelerating. It’s always worrying when you hear an unfamiliar sound coming from somewhere in your car and you’d be forgiven for thinking that if you don’t do something about it the problem might grow. As a result noises cause anxiety and can even distract you from keeping your eyes on the road.

There are plenty of resources on the web that can help you identify sounds, from banks of recordings that give you an idea of the causes of the audio aggravation through to YouTube videos that go through potential creaks and groans in detail. As ever the web is your friend and has the potential to be one of your greatest resources in keeping any vehicle trouble free.

In this guide we go through some of the basics that should help you get a rough indication of what might be going on behind the scenes in your vehicle. Use the information here to stay on top of potential difficulties and as a dipstick to tell you which troubles you might want to investigate further.

From the engine and transmission

Tapping, clattering or knocking – this sound originates from the engine and is most like caused by the valve lifters or in the worst case, issues with the crank shaft or bearings. Light tapping and you may need to adjust the valve clearances, heavy knocking, and it’s anything from crankshaft bearing issues or even a failed big end.
Screeching, squealing, wailing – hold your ears as this high friction sound makes its way from your fan belt when your car is accelerating. Usually a sign of wear. Either the rubber is failing and has become weak or you’re looking at issues with the tensioner or the pulley wheels.
Hissing – from under the bonnet of the car, indicating the escape of air from the air or fuel systems, or in some extreme cases, this could indicate head gasket issues. Look for coolant leaks. Hissing when the car is turned off is probably due to cold fluid leaking onto hot engine parts.
Clicking, tapping or knocking – the most likely culprit here is either a low oil level in the engine preventing good lubrication or an oil blockage, again preventing flow of oil. If there is no problem with the oil flow system then the valve train will need checking as the valves may have totally collapsed.
Rattling, pinging or hammering – making its way out of the bonnet when you accelerate or the car is under load is probably coming from misfiring pistons. Could be one of three problems, detonation, pre -ignition or spark knock. All of these spell one costly repair.

Grinding or crunching – if this horrible noise occurs when changing gear either manually or automatically, it’s a problem with gears wearing or the gearbox synchronisers, which allows for the easy shifting of gears or the clutch. Usually comes paired with high mileage on the clock.

From the brakes and suspension

Scraping or metallic screeching – not such a bad sound as brake pads are often designed to have a metal tag that creates a high pitched noise to indicate the pads need changing. The noise comes from the tag rubbing up against the rotor.
Clunking – this slightly shocking sound when you brake is often accompanied by a lack of response from the pedal. The main cause? Usually a sign that a calliper is either damaged or simply mounted incorrectly.
Whistling, scraping, rattling – don’t confuse this one with a wheel bearing failure. The usual culprit is a stone that’s caught between the brake disc and the cover and the noise is the vibration resonating through the entire system.
Knocking or clunking – when you go over pot holes or bumps in the road? Suspension is usually the answer, and the cause is likely to be anything from bad ball joints, worn control arms or faulty stabiliser pins. Further investigation is often required, but a simple bounce test can help confirm issues.

From the rear of the car

Loud bang – back-firing from the car? The likely cause is down to a poor mix between fuel and air which leads to explosions in the exhaust system or could be down to deeper issues within the catalytic converter.
Rasping or roaring sound – whilst accelerating is indicative of a problem with the car’s exhaust. Usually a simple fix. Buy a new part at a tyre and exhaust centre. If this noise is accompanied by a scraping sound then it’s likely a bracket has bust too and you are hearing the exhaust scrape on the tarmac.
Howling, Whirring – usually a symptom of a problem with the differential. This complex system has a number of fatigue prone parts and pinion preload, bad bearings or worn gears are the most likely originators of the sound.

When Steering or Turning

Clunking or Clacking – listen for a sound that’s not dissimilar to a train passing over the tracks. The cause? You are looking at excessive wear on the constant velocity joints (CV joints) which can be found located at the end of drive axles.
Groans or Moans – when steering or turning? If your car still has a hydraulic power steering system then the most likely cause is a broken down power steering pump that’s losing pressure. Get it seen to or you could lose the ability to turn whilst out on the road.
Screeching – this high pitched noise is due to issues with the power steering belt in the car, which will need adjusting to resolve the issue.

And finally…

As with any problem, fast action can often prevent knock on damage and secondary issues. For instance if you have a blockage in the oil system, the lack of lubrication could impact the workings of your engine and could even see a major problem with an expensive part.

If you do hear a new sound coming from your car, then it is always best to take it to a mechanics and get them to investigate further, or if you have enough knowledge, perform an inspection yourself. Where necessary replace any faulty parts at your earliest opportunity to prevent motoring failures when out on the road.