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What Car? Reliability Survey: Most and least reliable coupés, convertibles and sports cars

In our annual Reliability Survey, we ask readers to rate the dependability of cars aged up to five years old. Here we list the most and least reliable coupés, convertibles and sports cars...

Audi TT and BMW Z4 sports car reliability header

Coupés, convertibles and sports cars are cars you buy for fun, but getting one that's unreliable and costly to keep on the road will quickly dent your enthusiasm. 

The good news is that these cars are generally robust, providing fault-free driving for most owners. The class has had an average score of 92% for the past couple of years, and some cars frequently appear at the top of the chart. 

How we compiled the survey

To create the latest What Car? Reliability Survey – conducted in association with MotorEasy – we asked 21,732 drivers to tell us about any faults their cars had suffered in the past 2 years.

For each of these, we asked owners how long the car spent in the garage, and how much it cost to put the fault right. This data allowed us to create definitive reliability ratings for 178 models from 32 brands.

To help warn potential buyers about common problems, we also noted where the faults occurred, asking owners to choose from 14 different component areas. 

For this story, we've pulled out all the data for coupés, convertibles and sports cars aged up to five years old. 

The 2024 What Car? Reliability Survey is live, tell us about your car now

Most reliable coupés, convertibles and sports cars

1. Audi TT (2014-2023)

Audi TT front right driving

Reliability rating 98.4%

What went wrong? Air-con 7% 

The Audi TT looks great, is fun to drive and, above all, is dependable. A mere 7% of the cars reported on had any issues – all relating to the air-con system – and all of those were resolved at no cost to owners. All the faulty cars could still be driven, and only the fact that niggles took up to a week to repair took some of the gloss from the ownership experience.

Owner’s view: “My first TT was reliable enough to prompt me to buy my second.”

2. Mercedes CLA (2019-present)

Mercedes CLA nose cornering

Reliability rating 97.9%

The Mercedes CLA is based on the same underpinnings as the Mercedes A-Class yet suffers fewer faults than its stablemate. Only 14% of CLAs went wrong (compared with 31% of petrol and hybrid A-Class saloons and 39% of diesels). All CLAs were fixed at no cost to owners and all were back on the road in less than a week.

3. Mini Convertible (2016-present)

Mini Convertible front cornering

Reliability rating 97.1%

The Mini Convertible is one of the cheapest four-seat convertible cars you can buy. It’s also the most dependable. Only 11% went wrong, with brake, engine or sat-nav/infotainment system issues. Mini paid for all repairs, all cars could still be driven and a third were put right within a day, but the rest took more than a week.

4. Toyota GR Yaris (2020-2022) 

Toyota GR Yaris 2021 front

Reliability rating 96.7%

Toyota has a strong reputation for building reliable cars, and the Toyota GR Yaris hot hatch is no exception. Indeed, only 7% of respondents’ cars suffered a fault, with non-engine electrics cited as the main culprit in all cases. However, all repairs took more than a week, and cost owners as much as £300.

=5. BMW 2 Series Coupé/Convertible (2014-2021) 

BMW 2 Series Coupe front right driving

Reliability rating 96.4%

Both the convertible and coupé versions of the 2014-2021 BMW 2 Series represent good value for money on the nearly-new market, especially when you consider how well they performed in this survey. One in six cars suffered a fault, but of these a majority were minor; in all cases the car remained driveable, and 88% of faults took less than a day to put right.

=5. Porsche 718 Boxster/Cayman (2016-present) 

Red Porsche 718 Boxster front right driving

Reliability rating 96.4%

Our two favourite sports cars, the hard-top Porsche Cayman and convertible Porsche Boxster, not only offer excellent performance, but promise decent reliability too. Sure, 21% of cars suffered a fault – with either the air con, bodywork or non-engine electrics – but none rendered the car undriveable, and all were fixed under warranty, at no cost to the owner.

7. Audi A5 Coupe/Convertible (2018-present) 

Audi A5 Coupé front right static

Reliability rating 94.9%

The two-door Audi A5 coupe and convertible are less troublesome than the four-door coupe Sportback version. Only 17% of owners told us their car has had any issues, and the only areas concerned were the brakes, exhaust, fuel system and interior trim. All cars remained driveable, and 40% were fixed in a day or less; the rest were back on the road in less than a week. The only slight concern it that, although Audi covered the cost of 80% of repairs, the remaining 20% of owners had to find up to £750 to get their cars fixed.  

8. Jaguar F-Type (2013-present) 

Jaguar F-Type

Reliability rating 91.0%

If the big Jaguar F-Type discounts available through our New Car Deals service have caught your attention, you’ll be pleased to know that a Jaguar F-Type should prove a reliable purchase. Just 12% of cars suffered a fault, with the majority of those relating to non-engine electrics.

However, if something does go wrong, the news isn’t quite so good. All faults took more than a week to repair, while a third left cars undriveable until they were put right. And, while most issues were sorted out under warranty, one owner had to shell out more than £1500.

=9. Mercedes C-Class Coupé/Cabriolet (2016-present) 

Mercedes-Benz C-Class Coupé

Reliability rating 89.7%

As a brand, Mercedes performed poorly in this survey, finishing 24th out of 32; 12 places behind close rival BMW. The Mercedes C-Class Coupé and Cabriolet, however, are the exception to the rule, proving rather more reliable than the rival BMW 4 Series (more on that car below). Although 27% of two-door C-Class owners reported a fault in the last two years, all cars remained driveable, and all repairs were carried out under warranty.

=9. Mazda MX-5 (2015-present)

Mazda MX-5 front cornering

Reliability rating 89.7%

The Mazda MX-5 is the most affordable new sports car on the market, and its great-value thrills are complemented by minimal repair bills – in most cases. Around a fifth of cars in our survey went wrong, with faults related to the battery, bodywork, engine electrics and suspension reported. Fortunately, all took less than a week to put right, but 22% prevented cars from being driven until they were repaired. Two-thirds of repairs set owners back less than £200, but some reached as much as £1000 for a single repair.

Least reliable coupés, convertibles and sports cars

1. BMW 4 Series Coupé and Convertible (2014-2020)

BMW 4 Series Coupe 2020 front cornering

Reliability rating 83.0%

What went wrong? Battery 9%, bodywork 9%, non-engine electrics 6%, air-con 3%, brakes 3%, fuel system 3%

The 2014-2020 BMW 4 Series isn’t particularly prone to problems, but when they do occur, they can be pricey and slow to fix. BMW covered the cost of only 42% of repairs, leaving nearly half the owners with bills of up to £1500 and 8% paying more than that. Overall, 21% of cars went wrong, and while 42% were fixed in a day or less, 50% took more than a week to put right. As well as the coupé version, the figures cover the 2014-2020 BMW 4 Series Convertible.

Owner’s view “I’ve spent more than £3000 in the past year due to a coolant leak and resultant damage to the wiring harness – very disappointing.”

2. Volkswagen Arteon (2017-present)

VW Arteon Shooting Brake front right driving

Reliability rating 86.6%

Issues affected 32% of Volkswagen Arteon cars reported on for our survey, with the sat-nav/infotainment system playing up in 27% of those. Although Volkswagen covered the cost of 82% of remedial work, 9% of owners had to find more than £1500 to have their cars put right. Around a third of the affected cars were off the road for more than a week.

3. Porsche 911 (2019-present)

Porsche 911 2022 front

Reliability rating 87.3%

Bodywork faults were the main bugbear of Porsche 911 owners, accounting for 25% of all faults. Overall, 33% of 911s had issues, with owners also reporting battery and interior trim faults. Two-thirds took less than a week to fix, but although Porsche paid for 80% of repairs, 20% of owners faced bills over £1500.

4. Mercedes E-Class Coupé/Cabriolet (2017-present)

Mercedes E-Class Coupe front cornering -red

Reliability rating 87.6%

These two models major on comfort and refinement – the Mercedes E-Class Cabriolet is wonderfully quiet when on the move, even with the roof down. However, the atmosphere may become rather less tranquil once you know that a third of drivers surveyed reported a fault with their two-door E-Class. Cars did at least remain driveable in all cases, but 50% of problems took more than a week to fix, and one in six racked up a bill of more than £1500 in the process.

5. Audi A5 Sportback (2016-present)

Audi A5 Sportback front right driving

Reliability rating 89.0%

Electrical issues were a concern for many of the 23% of Audi A5 Sportback owners who told us their cars had gone wrong. The most common areas of complaint were the air-con anf various electrical systems. There were also some reports of problems with the battery, engine and exhaust system. While two-thirds of remedial work was done for free, 13% of owners faced bills exceeding £1500, and 50% of cars were out of action for more than a week.  

To read the reliability data for other car classes follow these links:

All cars and SUVs here
Most reliable small cars
Most reliable family cars
Most reliable executive cars
Most reliable luxury cars
Most reliable small SUVs
Most reliable family SUVs
Most reliable large SUVs
Most reliable seven-seaters
Most reliable electric cars
Most reliable electric SUVs
Most reliable car brands
Most reliable diesel cars

Reliability of coupés, convertibles and sports cars aged up to five years old

Rank Make and model Score
1 Audi TT (2014-2023) 98.4%
2 Mercedes CLA (2019-present) 97.9%
3 Mini Convertible (2016-present) 97.1%
4 Toyota GR Yaris (2020-2022) 96.7%
5 2014-2021 BMW 2 Series Coupé / 2014-2021 BMW 2 Series Convertible 96.4%
6 Porsche 718 Boxster / Porsche 718 Cayman (2016-present) 96.4%
7 Audi A5 Coupé / Audi A5 Cabriolet (2018-present) 94.9%
8 Jaguar F-Type (2013-present) 91.0%
9 Mercedes C-Class Coupé / Mercedes C-Class Cabriolet (2016-present) 89.7%
10 Mazda MX-5 (2015-present) 89.7%
11 Audi A5 Sportback (2016-present) 89.0%
12 Mercedes E-Class Coupé / Mercedes E-Class Cabriolet (2017-present) 87.6%
13 Porsche 911 (2019-present) 87.3%
14 Volkswagen Arteon (2017-present) 86.6%
15 2014-2020 BMW 4 Series Coupé / 2014-2020 BMW 4 Series Convertible 83.0%

About the report author

Claire Evans has been a motoring journalist for more than 30 years, and has focussed on consumer issues for much of that time. She was the advice columnist for Carweek magazine in the 1990s, helping car owners with faulty cars get the right level of reparation from car makers.

She also spent six years working on motoring content for Which?, and it is here she oversaw the running of the charity's annual used car reliability survey.

Claire launched the What Car? Reliability Survey in 2017, and since then has helped thousands of buyers choose the most reliable new cars and SUVs, as well as the most dependable used cars.

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