The most & least reliable executive cars

So, as well providing a plush and practical interior, good mile-munching ability and the latest in-car technology, they need to be robust – and that's where our Reliability Survey comes in.

We asked nearly 13,000 people to tell us about any faults their cars had suffered during the past 12 months. We asked how long each problem kept the car off the road and how much (if anything) the repairs had cost.

Those cars that suffered the fewest problems and were cheapest to fix gained the highest scores, while those that languished in workshops for days on end and racked up expensive repair bills were penalised the most heavily.

Here we count down the most and least dependable executive cars aged up to five years old.

Score 95.0%
Owners told us that diesel 3 Series models went wrong more than twice as often as petrols; 22% of diesel cars had a fault compared with 9% of petrol ones. Non-engine electrics were the main cause of concern, followed by the exhaust system, bodywork, engine and infotainment system.

Almost all cars could still be driven, though, and 49% were repaired in a day or less. Warranty work covered the cost of 68% of work and most other repair bills ranged from less than £50 to £300.

Score 95.1%

Only 19% of V60s suffered a fault, with problem areas including air-con, the battery, bodywork, brakes, exhaust, interior trim and non-engine electrics. More than three quarters of cars could still be driven and half were put right in a day or less.

Three quarters of cars were fixed under warranty and the others cost owners between £201 and £300.

Score 96.3%

Owners told us 22% of their A3 Saloons went wrong, with non-engine electrics the most common issue. Other problematic areas included the bodywork, brakes, gearbox and infotainment. Three-quarters of cars remained driveable, and more than half were repaired the same day.

Nearly a third were fixed under warranty, but another 29% cost more than £1500 in repair bills.

Score 96.7%

Bodywork and non-engine electrical issues were the main bugbears of Optima owners; 21% of their cars suffered a fault. All cars could still be driven, though, and two thirds were back on the road in less than a week.

Even better news - all cars were fixed for free.

Score 97.0%

Only 14% of Mondeo owners reported a fault with their car, and the most commonly afflicted area was engine electrics. There were also a small percentage of problems with the air-con, exhaust, interior trim and infotainment.

All cars were driveable and nearly three quarters were put right in a day or less. More than 70% of work was done for free and no repair bills topped £50.

Only 25% of cars were fixed for free, and other bills ranged from under £50 to £750.

Score 97.8%

Although 23% of Insignias went wrong, two thirds of cars could still be driven and a third were rectified in a day or less. Problem areas included the air-con, engine, suspension and engine and non-engine electrics.

More than 20% of cars were fixed under warranty and most repair bills were less than £300.

Score 98.0%

Only 14% of Mazda 6 owners reported a fault with their car, with the main area of concern being the infotainment/sat-nav, followed by the engine. Fortunately, all of the afflicted cars could still be driven and 75% of the problems were rectified in a day or less.

All repair work was carried out for free under warranty.

Score 98.3%

What went wrong? Engine 2%, interior trim 2%, non-engine electrics 2%

If you want a dependable Superb, pick a petrol model, because only 10% of them went wrong, compared with 24% of those with diesel engines. Half of the faulty cars we were told about were repaired in a day or less and 75% of them remained driveable.

Even better news, all cars were fixed for free.

Score 99.4%

What went wrong? Interior trim 5%

Tesla's newest model is the most durable executive car, with just 5% of cars suffering a fault, according to owners. All cars could still be driven and were fixed in a day or less at no cost to the owners.

Owner’s view: "Everything about this car is superb, and I've had none of the build quality issues of the earlier models"

So that's the most reliable executive cars - what about the least?

Score 89.8%

Diesel versions of Audi’s executive saloon were marginally less dependable than petrol versions, with 24% of them going wrong, compared with 21% of petrols. The battery was the biggest issue, followed by non-engine electrics, and then the bodywork, brakes and suspension. Although most cars could still be driven, a third took more than a week to fix; 80% of work was done under warranty and only a small percentage of owners paid out £1500 or more.

Score 87.4%

A quarter of Insignia owners reported a fault on their car, with the gearbox/clutch causing the most concern. Other problem areas included the bodywork, engine, engine and non-engine electrics and the suspension. Nearly half of the cars couldn’t be driven and were out of action for more than a week. Thankfully, four out of five were fixed for free.

Score 87.3%

What went wrong? Non-engine electrics 11%, exhaust 6%, fuel system 4%, battery 3%, bodywork 3%, infotainment/sat-nav 3%, brakes 2%, steering 2%, engine 1%, gearbox/clutch 1%, interior trim 1%

A third of C-Classes went wrong, according to owners, who reported a wide range of issues. Faults rendered more than a third of cars undriveable, and one in four was off the road for more than a week. Although 81% of cars were fixed for free, a small percentage of owners paid out more than £1500 in repair bills.

Owner’s view “This is the worst car I have ever bought. Faults haven’t been properly fixed and the service from the dealer has been poor.”