About our car reliability survey

About our survey

Owners told us about serious, major and minor faults that happened in the past year. We also asked them how satisfied they were with their car and specific aspects of its performance.

Our survey was conducted during November and December 2023. We received data on 8527 cars. We only analysed makes or models that received more than 30 samples.

We report predicted reliability and owner satisfaction as one of five rating bands: highest, high, average, low or lowest. The rating is determined by comparing the results for a make or model with those for all vehicles in our dataset.

Predicted reliability

Our reliability index, scored from zero to 100, includes faults reported in our survey – with more weight given to serious faults and less to minor niggles.

To achieve a perfect score of 100, a brand or model would need to have no faults reported. Spoiler alert: no brands or models in our survey scored 100.

Our index allows for age: if a brand or model has better (or worse) reliability than you’d expect for the age of the cars in its sample, our index accounts for it. This means brands and models with older cars aren’t penalised unduly.

Reporting faults

We wanted to know about reliability problems that happened in the past year. We asked respondents to tell us if they thought the fault was serious, major or minor.

• Serious faults are likely to cause a breakdown, take a car out of service for more than a few days and be expensive to repair.
• Major faults could still cause breakdowns or result in significant repair costs and time off the road.
• Minor faults are less critical, but may still need repair or affect owner satisfaction.
• Cars with no serious, major or minor faults were reported as trouble-free.

Owner satisfaction

We asked owners how satisfied they were with their car and if they’d recommend this make and model to family and friends. Answers were rated on a 0-10 scale; we considered a rating of 8-10 as “very satisfied” or “very likely to recommend”.

We asked about satisfaction with different aspects: fuel economy, comfort, driving performance, safety features, size and practicality, interior styling and equipment and value for money.

We also asked “given your experience with this car, would you still have chosen this make and model at the time you purchased it?”

Finally, we asked owners to tell us how much they’d spent on servicing and repairing their car in the last year. Servicing included regular costs to maintain their car, including WOF fees and replacing wear and tear items such as tyres. Repair costs covered everything else – breakdowns and unplanned repairs.

Tips for using our survey data

• Take care when using reliability data for recent models. Models available for just a few years are likely to top our reliability index. This isn’t surprising – after all, they’re effectively new cars.
  
• Current reliability doesn’t necessarily indicate how well, or badly, a model will age. Look where older models from the same brand sit in the index.
• Check out the brand’s overall performance. It’s unlikely a brand with a history of below-average performance will suddenly create a reliability superstar (but you never know).
• Not all cars from a more reliable brand will be reliable. Our data show trends and statistically significant results from a sample of almost 10,000 cars. But even among the best-performing brands and models, there’ll always be examples of cars with problems.