Diagnose Strange Noises In Your Car & Find A Fix
FixMyCar discusses how to diagnose and fix common car noises.
Book a car repair nowEllie Dyer-Brown
Wednesday November 08 2023
12 min read
When you regularly drive the same car, you become attuned to its noises - the rumble of the engine, the whir of the heating vents. This familiarity makes it easier to notice when a new noise appears, even if it’s quiet.
Whether your car has started squeaking, knocking, thumping or hissing, strange noises shouldn’t be ignored. They are usually the sign of an underlying problem, which may get worse over time.
This guide will help you tackle unusual car noises head-on by providing an overview of all the sounds you might hear, an explanation of what can cause them, and the type of repair that may be required.
My car sounds louder
When your car sounds louder than usual but hasn’t started making a new noise, you should still investigate the problem to determine whether it requires a trip to the garage.
The first thing to ask yourself is whether your car sounds louder at the front or the back.
A louder sound at the rear of the car indicates an exhaust problem, such as a corroded pipe or faulty silencer. If the damage is too extensive for a repair and you need to book an exhaust fitting, you can expect to pay £129.60 on average based on FixMyCar’s data.
On the other hand, an increase in volume at the front could be explained by low engine oil, worn bearings or a defective torque converter (in automatic transmission cars). You can identify low engine oil yourself, but for the other possibilities, it’s best to book an engine diagnostic.
My car is making a scraping noise
Scraping noises are a common problem in older vehicles. Most of the time, brake components are to blame, but transmission problems can also cause scraping sounds, particularly when you’re accelerating.
If you notice the sound when you turn a corner, one of your wheel bearings could be worn. Bearings facilitate the smooth rotation of the wheel while driving, so when they are faulty, you’ll often hear a scraping or grinding sound when you turn in a particular direction.
Other common explanations include worn brake pads, a twisted brake shield or debris stuck in the brakes. On average, brake repairs cost £316.89 when you book through FixMyCar.
You can find out more about why cars sometimes make scraping noises here.
My car is making a clunking noise
Clunking is one of the more alarming car noises because it suggests that two metal components are hitting or rubbing against each other with some force. The easiest way to work out what’s going wrong is to pay attention to when the noise happens.
Clunking when you start your engine may happen due to transmission problems or a faulty starter motor. Unfortunately, neither of these issues is cheap to resolve.
Replacing a starter motor costs £256 on average when booked through FixMyCar.
Regarding the transmission, there could be a number of things at fault, such as:
Broken teeth on the flex plate
Low or old transmission fluid
Broken engine/transmission mounts
Faulty internal transmission components
Read more about why your car might be making a clunking noise in this guide.
My car is making a grinding noise
Typically, grinding indicates that two components are rubbing against each other without lubrication, which isn’t a good sign. The longer it is left unchecked, the more damage may occur.
There are five likely explanations for a grinding noise:
Damaged water pump
Worn alternator
Worn wheel bearing
If the noise happens while the engine is running, it’s likely to be the water pump or alternator, and if it only happens when you switch the aircon on, it’s probably caused by a bad compressor.
Grinding when you change gears usually indicates a bad clutch, and if the noise speeds up and slows down as you do, getting louder when you turn, it might be a wheel bearing. Worn or damaged parts will need replacing by a mechanic to eliminate the noise.
My car is making a hissing noise
As with most unusual car noises, the cause of hissing can often be diagnosed by working out where the noise originates.
If the hissing comes from your engine, it’s probably because your car is overheating. Low coolant is the most likely reason, but there are other possible explanations. It’s worth seeing if you can spot any puddles of leaking coolant around the engine or under the car - if you do, you’ll have to book a leak repair.
Hissing when you have your AC switched on suggests there may be a problem with the air conditioning valve responsible for keeping the refrigerant gas compressed. The best way to determine whether this is the case is to book an aircon service to assess the condition and functionality of your car’s AC system.
Finally, a hissing noise when you accelerate is probably related to an exhaust system leak or a damaged hose in the cooling system.
My car is making a thumping noise
The key areas to look at when investigating a thumping noise are your car’s brakes, suspension, tyres and transmission.
Warped brake rotors may be to blame for the thumping sound if you have also noticed reduced braking performance and a vibrating steering wheel. Discs are particularly susceptible to the excessive heat caused by friction, which may lead them to become warped, causing an unusual sound when you hit the brakes.
You can inspect your discs to rule this explanation out - they are the circular metal components visible behind each wheel, so it’s easy to spot damage.
While inspecting the brake discs, pay close attention to your tyres. Are they worn unevenly? If so, this may explain the thumping. Misaligned wheels are the most likely reason for uneven wear, but it could also be due to faults with the steering, suspension or braking systems.
As you’ve probably noticed, making a diagnosis isn’t always straightforward.
My car is making a clicking noise
There are many reasons why your car might be making a clicking sound, ranging from low engine oil (an easy and cheap fix) to a faulty CV axle (less easy and affordable to repair).
A single click may be caused by a defective starter motor, which usually lasts between 20,000 and 200,000 miles. A rapid clicking noise, on the other hand, is more likely to be the result of a faulty alternator or battery.
A starter motor repair costs £256 on average, based on FixMyCar’s data, while a battery replacement is more affordable, at £181.
However, these are just a few possible explanations.
My car is making a knocking noise
It’s much easier to work out why your car is making a knocking noise when you focus on the area where the sound is coming from. Mainly, knocking is caused by damaged or worn components that need replacing.
If the sound comes from inside the engine, it may be caused by low oil pressure, a faulty cambelt, worn bearings and a range of other things discussed here.
Outside the engine, worn wheel bearings could be to blame, especially if you notice the sound when you turn corners.
My car is making a rattling noise
Rattling is arguably one of the most annoying noises, especially when you’re on a long drive and don’t know how to get rid of it.
When the rattling is underneath your car, a loose exhaust system or faulty suspension might be to blame. Under the bonnet, low engine oil or a cracked serpentine belt are the most likely culprits, while rattling that happens when you accelerate could be caused by a broken catalytic converter.
If you’re lucky, the rattling might be coming from a loose item inside the cabin that you can locate and remove yourself.
My car is making a whistling noise
A whistling noise has fewer possible explanations than most other unusual car noises, making it easier to diagnose. First, pay attention to whether the whistling happens while you’re driving, when you accelerate, or after you switch the engine off.
Possible causes include:
Loose, worn or wet serpentine belt
Worn window seals
Faulty radiator pressure cap
My car is making a ticking noise
Ticking noises aren't uncommon in cars; some are perfectly normal. If your car has always made a rhythmic ticking sound that's relatively quiet, you needn't worry. Some components naturally make a ticking sound, such as the PCV valve.
However, ticking can indicate a problem when it is caused by:
Low engine oil
Damaged engine oil filter
Broken or misaligned valves
Dirty or worn lifters
Faulty spark plugs
Knocking engine rods
Leaking exhaust manifold
My car is making a whining noise
There’s no denying it: whining noises are annoying whether they come from a child or a car. And while a child can tell you what's wrong with them, finding answers from your vehicle is not so straightforward. However, with a bit of research, it is possible to work out what’s causing the noise.
If the whining noise happens when turning, there’s probably an issue with your power steering system. Firstly, check the fluid level. If it’s low, there may be a leak. It’s also worth inspecting the steering belt for signs of damage or whether it has come loose.
A whining noise when idling suggests your engine oil may be low, or one of your valves may be stuck. You can check and top up your engine oil, but you'll need to book a repair if there’s a leak or valve problem.
Transmission problems could be to blame if you notice the whining noise when accelerating. Other possible explanations include low power steering fluid, a malfunctioning water pump, a defective AC compressor or faulty alternator bearings. The best course of action in this case is to find a mechanic to identify the cause of the noise.
My car is making a squeaking noise
When your car starts making a squeaking noise, it can quickly wear away at your sanity if left unchecked - not only because the problem may be getting worse but also because it’s incredibly annoying.
What’s even worse is that there are many possible explanations for what might be causing the noise. For example, a worn fan belt could be to blame if you notice the squeaking when you accelerate, while low power steering fluid might be the culprit if the noise happens when you turn.
It’s easy to tell when your brakes are to blame for the squeaking but not so easy to identify the problematic component - is it the pads or rotors that need replacing?
My car is making a squeaking noise when I turn
Often, a squeaking noise when you turn can be attributed to one of four things: a faulty component in the power steering system, a lack of power steering fluid or suspension lubrication, driving on certain road surfaces (particularly if you turn a sharp corner while going fast), and parts of the cabin’s interior trim rubbing against each other.
My car is misfiring
Misfiring suggests something is going wrong in your engine, and it is usually caused by one of five things.
A problem with the ignition system is often the reason cars misfire. The best-case scenario is that your spark plugs need replacing, which is a cheap and easy job, but several different ignition components could be at fault.
Other areas worth investigating are the sensors, which may be sending incorrect information to the ECU; the timing belt, which could be causing low compression; low pressure in the fuel system; and the intake manifold gasket, which may be leaking.
My car alarm keeps going off
We’ve all been there: it’s the middle of the night on a quiet street, and suddenly, for no apparent reason, somebody’s car alarm starts going off. Nothing makes people’s blood boil like being disturbed by an unnecessary alarm, but sometimes it can’t be helped. Like any part of your car, the alarm system can develop faults.
It could be something simple and easy to fix, like the key fob needing a new battery or the doors not being closed properly, or it might be something more serious, like a wiring issue or faulty door lock sensor, both of which require expert attention.
Still not sure what’s causing the strange noise in your car? Book a vehicle diagnostic test, which includes an inspection of the key components and should identify the source of the noise.
If you found this guide helpful, you might also like…
- Related topics:
- Banging Or Knocking Noise
- Diagnostic
- Diagnostics
- Hub
- Squeaking Or Squealing Noise
- Ticking Or Rattling Noise
