2011's most reliable cars

We look at which manufacturer, and which model, is the most reliable based on frequency of failures and repair costs.

For 2012's most reliable cars, please read 2012's most reliable cars

I live in Munich, home of BMW, where half the city seems to work for the car firm in some capacity. Even I do some translation work for it in my spare time. The car manufacturer's attention to detail on safety, reliability and performance, astounds me. They are perfectionists.

That's why it surprised me that it has not come out too well in Warranty Direct's reliability index, being in just 26th place. Indeed, German cars score relatively badly, on the whole.

Warranty Direct compiles its figures from around 50,000 car-warranty policies, each of which represents one car. It ranks both manufacturers and individual models on reliability, based on the frequency of failure and repair costs.

Which manufacturer is the most reliable?

Top of the manufacturers' table is Chevrolet. It scores 20 points in a points system where the closer you get to zero, the better. Land Rover comes out worst with 206 points.

Chevrolet is a bit of an anomaly, however, because Warranty Direct has few Chevrolet policies, which makes the manufacturer's position in the index more susceptible to chance. Although the manufacturers' reliability index generally requires there to be at least 50 cars, this is still quite a low number, so it may be we can't take Chevrolet's position too seriously.

The number two on the list, Honda, could be our first real contender, as it has more cars insured by Warranty Direct, and so it's probably more accurate. Honda scores an impressively low 30 points.

Manufacturers' reliability index

Age might have something to do with it

The 50,000 vehicles used to compile this index are of varying age. Naturally, older cars will normally have had more use out of them, and so they will have become less reliable. That's why we should adjust the rankings to reflect the age of the vehicles used.

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The Chevrolets used in the index have the lowest average age of 3.7 years, making its first place on reliability even less impressive. Suzuki was assisted to third place on reliability by the relatively young age of its vehicles, too.

This bumps up Honda, Toyota and Hyundai from second, third, and fifth.

Yes, Honda is our winning manufacturer

Although Hyundai was third of the three, it has a reliability score just one point higher than Toyota's at 57 points, but the average age of the Hyundais in the index is more than six years versus the Toyotas' average of 5.1 years. Therefore the Hyundais have shown themselves to be more reliable at an older age, so I rank it second, above Toyota.

The Hondas average just 5.1 years old too, but with the manufacturers much better reliability score of 30 it takes first place.

To defend my sometimes employer, the BMWs used in the index are on average the 28th oldest, so in that regard coming 26th on reliability doesn't seem so bad.

Top individual models

Warranty Direct also has an index for 240 individual models. Again, to make the list there generally needs to be at least 50 vehicles of the model type.

Warranty Direct reveals the top ten most reliable cars as well as the bottom ten:

Models' reliability index – top 10

As you can see from the table, the Toyota Corolla does particularly well with an almost perfect reliability score of just four, even though the average mileage of the Corollas used in the index is very high.

Now the losers:

Models' reliability index – Bottom 10

My colleagues at BMW will be pleased to see so many of their Stuttgart enemies, Mercedes, in the bottom pile. The Mercedes-Benz SL comes out worst with a hideous score of 349.

I don't think this index is perfect. Notice that the worst-rated cars have, on average, much more mileage than the top ten. Low numbers of models may also influence the position of a model on the table, and a single outstanding vehicle, if particularly popular, could boost or punish the manufacturers' rankings too. But I think the reliability index could be a useful extra guide when you're comparing your own car or looking to buy a new one.

How reliable are the most popular cars?

Finally, based on searches on the popular UK website Autotrader, we can guess what the most popular cars are. Here's how the top five most popular cars score on reliability:

Reliability of UK's most popular cars

(Ranked by popularity)

Of the UK's most popular cars, the Ford Focus wins on reliability.

Reliability isn't everything. Autotrader says the BMW has low running costs and emissions, and cutting-edge technology, whereas the Golf holds its value surprisingly well. And that's not to mention comfort, style and performance. These aren't accounted for in the index.

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