Most and least reliable medium carsMedium car reliability: best and worst

17 December 2014

Medium cars are the default choice for many families. However, picking an unreliable model can prove unpopular as well as costly, especially if you breakdown with a 2.4 children onboard.

Luckily, Which? collects reliability data each year for all classes of car. These are the results from the latest Which? Car Survey for medium-sized cars.

Make sure you help us to report on the most reliable cars next year by filling in the 2015 Which? Car Survey. It takes just 15-20 minutes to complete and you could win free fuel for a year*.

Most and least reliable new medium cars

Japanese brands are synonymous with reliability, and the Toyota Auris certainly puts this point into perspective in the medium car sector.

For medium cars up to three years old, the latest incarnation of the Auris (2012-) took top spot, with a 99% Reliability Score and average annual repair costs totalling a measly £3.

Snapping at the Auris's heels was…another Auris. The previous Auris Hybrid (2010-2012) dispels the myth that any car with battery power will be unreliable by posting a 98% Reliability Score. A 4% breakdown rate did mean the odd owner experienced a journey-halting fault, but most problems reported were very minor.

More surprisingly, the Renault Megane (2008-) hatchback was the third most reliable medium car, according to owners. A 97% Reliability Score is aided by a 0% breakdown rate, although average annual repair costs of £30 were slightly higher.

Least reliable new medium cars: BMW 1 Series hatchback (2004-2011) 79%, Alfa Romeo Giulietta diesel (2010-) 84%, Citroen C4 (2010-) 85%

Most and least reliable older medium cars

The Auris and Auris Hybrid are also among the top three most reliable models older than three years. The Auris Hybrid (2010-2012) came out on top, with a 96% Reliability Score and £15 average annual repair costs.

The previous-generation Auris (2007-2012) with petrol engines is the third most reliable older medium car, scoring 94%.

Splitting the two is the petrol-engined Mazda 3 (2009-2013). While it does have a 7% breakdown rate, its 93% reliability score is aided by average annual repair costs of just £19. The most common faults are with the battery and stop-start system on petrol models.

Least reliable older medium cars: Renault Megane (2002-2009) 66%, Peugeot 307 (2001-2008) 74%, Citroen C4 (2004-2010) 74%

More on this…

*The prize is free fuel for one (1) year based on 12,000 miles (average annual mileage in the UK), achieving 30mpg (miles per gallon) and the petrol price of 129.9p per litre (based on average petrol price between November 2013 to October 2014, provided by the AA). This works out at a fuel value of £2,362.15, but will be rounded-up to £2,500 (the “Prize”). Full details available on our FAQs page.