When a strange sound comes from under the car bonnet, most drivers like to think they know what's going on. Maybe it's just a loose belt, or perhaps the suspension's a bit off. But while diagnosing issues yourself can be satisfying, our new research shows that getting it wrong could lead to more expensive repairs down the line.
To find out how much drivers know about car problems just from the sounds the car is making, we conducted a nationwide study. We asked 2,000 drivers to diagnose real car faults based on actual engine sounds. The results? Confidence might be high, but many drivers struggle to correctly identify the problem at hand.
Our survey reveals that over half of British drivers (53%) claimed they were confident in their ability to diagnose a mechanical fault. This confidence, however, was not evenly distributed. Men were significantly more self-assured than women, with 64% of male drivers saying they could identify a problem compared to just 41% of women. Age also played a key role in confidence levels. Among drivers aged 25 to 35, almost three in four (74%) believed they could pinpoint an issue under the bonnet - that number dropped to just 37% among drivers aged 55 and older. Mercedes-Benz owners topped the confidence rankings, with 80% saying they'd know what was wrong with their car based on how it sounded.
But when put to the test, confidence didn't quite match up with reality. At least 70% of drivers misdiagnosed half of the car trouble sounds they listened to.
| Rank | Issue (Audio Cue) | % Misdiagnosed |
|---|---|---|
| #1 | Low power steering fluid | 82% |
| #2 | Wheel bearing issues | 81% |
| #3 | Seized engine | 72% |
| #4 | Loose or worn-out belt | 70% |
| #5 | CV axle issues | 70% |
| #6 | Bad suspension | 65% |
| #7 | Cooling system leak | 61% |
| #8 | Loose exhaust shield | 60% |
| #9 | Exhaust leak | 55% |
| #10 | Worn brake pads | 48% |
When played the sound of a seized engine, nearly three-quarters of participants (72%) misdiagnosed the fault, with the most common incorrect guess being wheel bearings.
One of the few problems drivers had better luck diagnosing was worn brake pads. Just over half of participants correctly identified the sound. Volkswagen drivers led the pack here, with 53% diagnosing it accurately.
When your car starts to make a strange sound, from rattling to hissing, we want to equip you with the knowledge and reassurance of what you may be dealing with. Listen to the clips below to understand what each problem may sound like.
Ignoring car problems isn't just risky, it's expensive. 35% of drivers admitted they have ignored a mechanical issue, only for it to cost them significantly more in the long run. Men were twice as likely to do this than women, with 41% of male drivers confessing they'd delayed repairs, compared to just 19% of women.
The financial hit from postponing repairs was substantial. On average, drivers spent an additional £400 due to avoidable delays, and more than one in five motorists (21%) said they ended up shelling out over £700 to fix a problem they initially ignored.
When it came to recognising problems accurately, not all brands fared equally. Despite Mercedes drivers being the most confident in their diagnostic skills, it was BMW drivers who came out on top overall. They were followed by Volkswagen, Mercedes-Benz, Ford, and Hyundai, to rank as the top five car owners most likely to correctly identify the sound of a broken car.
| Rank | Car Brand | Number of correctly identified problems (/10) |
|---|---|---|
| #1 | BMW drivers | 8 |
| #2 | Volkswagen drivers | 6 |
| #3 | Mercedes-Benz drivers | 6 |
| #4 | Ford drivers | 5 |
| #5 | Hyundai drivers | 5 |
Volkswagen drivers proved particularly adept at spotting a loose exhaust shield, with half correctly identifying the issue. In contrast, Chevrolet drivers not only scored the lowest on brake pad recognition, with just 27% answering correctly, but were also the least likely to take their vehicle to the garage when something sounded off. Just 16% said they'd go straight to a mechanic, making them the most hands-off drivers surveyed.
When something starts sounding suspicious under the hood, drivers respond in very different ways. Almost half (47%) of all participants said they would immediately seek professional help; however, more than a third (36%) admitted they'd wait up to a month before doing anything.
Mercedes-Benz drivers were the quickest to act, with 57% saying they'd take their car in straight away. Meanwhile, Audi drivers were the most relaxed, with nearly 29% willing to leave the issue for over a week, which is longer than any other drivers we surveyed.
The first course of action varied by age, too. Younger drivers aged 17 to 24 were more likely to turn to their friends or family for advice, while older drivers, particularly those aged 45 to 54, preferred to research the issue online. Interestingly, Mercedes-Benz drivers were the most inclined to attempt a DIY fix, while Volkswagen owners were most likely to hit the search engines before calling a mechanic.
The findings are clear, while many UK drivers are confident in their ability to diagnose what's going on with their vehicle, very few can actually do so when it counts. Misdiagnosing car faults isn't just a harmless mistake; it can lead to delays, escalating repair bills, and increased safety risks.
If your vehicle is prone to mystery noises and you're tired of playing amateur mechanic, it might be time to upgrade. Newer cars often come equipped with advanced sensors and onboard diagnostics that alert you to problems before they become critical. Selling your current car or leasing a newer model could provide the peace of mind, and real savings, you've been looking for. But always remember that trusted, reputable mechanics are there to make your life easier and ensure your safety behind the wheel. So, if your car starts to make any suspicious sounds, take it to be professionally checked.
This research was conducted by Censuswide, among a nationally representative sample of 2,000 UK drivers aged 17 and over, between 2nd and 7th April 2025. Each participant was asked to listen to the sound of a real car fault and identify what they believed was wrong with the vehicle.