What Car? Reliability Survey 2021

Our comprehensive survey reveals how dependable vehicles up to five years old are, based on the experiences of owners

The UK’S most and least reliable cars revealed, based on owners’ experiences

THE UK’S USED car market is booming, with demand frequently outstripping supply, and that’s sending prices of the most popular models up by as much as a third. This unique set of conditions means that more of us than ever are looking for guidance on the best second-hand cars to buy.

A crucial factor in choosing the best used car is reliability; if you buy a good one, you’re unlikely to have to pay out for anything other than consumables and servicing as it ages. Pick one that suffers a stream of costly faults, though, and the bills will soon start to rack up.

That’s where the annual What Car? Reliability Survey can help. We’ve asked more than 16,000 car owners to tell us if their car has suffered any problems over the previous year, and if so, in which areas. The 15 categories of fault are air conditioning, battery, bodywork, brakes, clutch and gearbox, engine, engine electrics, exhaust, fuel system, infotainment and sat-nav, interior trim, non-engine electrics, steering, suspension and other.

To gain an indication of how serious each fault was, we also asked owners to tell us how long the car was out of action for and how much the repairs cost. The worst offenders were off the road for more than a week and cost more than £1500 to fix, while those with minor niggles were usually put right in a day or less and were often fixed for free.

These two factors are more important than what actually went wrong, so we used a combination of them to calculate a unique reliability rating for each model we’re told about.

The 2021 What Car? Reliability Survey contains data about 178 models aged up to five years old, from 30 brands.