Nobody wants to buy an unreliable car. Not just because it could let you down at any given moment but the unavoidable repair costs you will encounter tend to pile up.
Fortunately, we can exclusively reveal new data to tell you which 10 cars are most likely to suffer from dependability issues - but also the ones that are best at avoiding them.
And not only that, we can tell you what the most common problems are with the unreliable models and when they're most likely to strike - just so you can prepare for the inevitable garage bills if you do own one.
Getting stranded by the side of the road is infuriating for motorists, which is why it's important to buy a reliable car
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Used car warranty provider Warranty Wise has given This is Money the list of the 10 most unreliable second-hand motors you could buy, based on the number of claims against faults and how much they cost.
'This data is not fictitious, it is derived from real cases and genuine warranty claims making it the most trustworthy information a used car buyer can get,' a spokesperson for the brand told us.
'We are not suggesting, by any means, that these problems are guaranteed to occur, but it is the sole reason a warranty exists.
'A proper, comprehensive warranty provides peace of mind to any buyer forewarned with this type of information, making any used car purchase a less risky and more comfortable experience.'
Each year, it lists the brands and models that are deemed the most and least reliable, according to the data it has collated in the previous 12 months.
Scroll down the page to find out which models and brands that have the fewest warranty claims for repair bills.
10 most unreliable models
1. Range Rover Sport
Expensive to buy and to repair: Warranty Wise says the Range Rover Sport is the most unreliable used car
Range Rover Sport most common faults repaired under warranty
| Fault | Ave Cost of Repair | Yr(s) Most Affected |
|---|
| Suspension Faults | £540.00 | 2009 |
| Alternator | £420.00 | 2008 |
| Brake Faults | £486.00 | 2009 |
| Electrical Faults | £324.00 | 2010 |
| EGR Valve Faults | £432.00 | 2008 |
The Range Rover Sport is a pricey SUV that's used by most for the school run rather than scaling mountain rises or trawling through fields.
That said, many still incur plenty of issues which tend to be expensive to repair.
Warranty Wise ranks it as the least dependable model you can drive, with the most common problem being suspension faults, which costs on average £540 to fix.
When problems start to pile up: when a car is 8 years and 7 months old
2. Vauxhall Zafira
No smoke without fire: Zafrias not only suffer from sporadic fires, they also have plenty of other pricey faults
Vauxhall Zafira most common faults repaired under warranty
| Fault | Ave Cost of Repair | Yr(s) Most Affected |
|---|
| Gearbox Faults | £1,080.00 | 2008 |
| Clutch Faults | £492.00 | 2007/8 |
| Ignition Coil | £186.00 | 2006 |
| Alternator | £246.00 | 2006-2009 |
| Electrical Faults | £336.00 | 2007 |
The Zafira is probably a car you've decided to avoid already - or you would have done if you'd Googled it. The family-friendly MPV has been subject to recalls following a spate of fires that have occurred, mainly caused by aftermarket replacement parts.
And turning into a fireball on wheels isn't all that owners need to be concerned about. That's because this Vauxhall suffers some catastrophic gearbox issues, which cost on average over £1,000 to resolve.
When problems start to pile up: when a car is 10 years and 3 months old
3. Vauxhall Insignia
Rep mobile with a ropy reliability record: Watch out for pricey engine and gearbox issues with the Vauxhall Insignia
Vauxhall Insignia most common faults repaired under warranty
| Fault | Ave Cost of Repair | Yr(s) Most Affected |
|---|
| Steering Faults | £276.00 | 2009/10 |
| Engine Faults | £1,230.00 | 2009/10 |
| Electrical Faults | £258.00 | 2011 |
| Gearbox Faults | £1,080.00 | 2010/11 |
| Heater/Glow Plugs | £144.00 | 2009 |
Vauxhall's second entry in the unreliable car list is the Insignia - a favoured rep mobile that's likely to have been slogged up and down the motorway in the week and used to cart the family around at the weekend.
According to Warranty Wise, it's steering faults that are most common, though the repair costs are a £276, though there are other frequently reported issues that cost almost five times as much to fix.
When problems start to pile up: when a car is 7 years and 7 months old
4. Peugeot 207
The token French entry: There had to be a French model in the top 5. And while the Peugeot 207s repair costs aren't that high, they are when you consider the value of the vehicle itself
Peugeot 207 most common faults repaired under warranty
| Fault | Ave Cost of Repair | Yr(s) Most Affected |
|---|
| Engine Faults | £816.00 | 2007/8 |
| Cylinder Head Gasket | £576.00 | 2007/8 |
| Clutch Faults | £204.00 | 2007/8 |
| Electrical Faults | £348.00 | 2007/8 |
| Gearbox Faults | £900.00 | 2007/8 |
French cars don't have the best reputation when it comes to dependability, but this is the only one to feature in Warranty Wise's top 5 rankings.
What goes wrong most often? According to the report, it's engine faults and cylinder head gaskets that tend to cause the most headaches. While these aren't as expensive to rectify as other models in this list, the relative cost in terms of the vehicle value is still pretty high.
When problems start to pile up: when a car is 10 years and 2 months old
5. Vauxhall Astra
Family hatch, but there's a catch: The Vauxhall Astra is a popular choice in the UK, but customers should buy with caution
Vauxhall Astra most common faults repaired under warranty
| Fault | Ave Cost of Repair | Yr(s) Most Affected |
|---|
| Gearbox Faults | £1,068.00 | 2005-2011 |
| Engine Faults | £600.00 | 2005-2010 |
| Alternator | £300.00 | 2006-2008 |
| Electrical Faults | £348.00 | 2008 |
| Clutch Faults | £528.00 | 2008 |
That's a hat-trick of Vauxhalls making the top five least reliable cars, according to Warranty Wise data. That's not good for the brand that was recently bought by the French PSA Group.
The Astra - which is the manufacturer's second best-selling model behind the Corsa in the UK - might be an affordalbe family hatchback, but keep hold of it for too long and it will become pricey to repair.
The most common warranty claim is for gearbox faults, which cost a staggering £1,000 on average to sort out.
When problems start to pile up: when a car is 9 years and 3 months old
6. Mercedes-Benz C-Class
A high price to pay: The Mercedes-Benz C-Class is one of the most popular junior executive saloons, but electrical faults and sensor gremlins are commonly reported
Mercedes C-Cass most common faults repaired under warranty
| Fault | Ave Cost of Repair | Yr(s) Most Affected |
|---|
| Electrical Faults | £372.00 | 2007-2009 |
| Sensor Faults | £222.00 | 2006 |
| Suspension Faults | £354.00 | 2006 |
| Engine Faults | £1,500.00 | 2005-2011 |
| Alternator | £456.00 | 2005 |
Like the Range Rover Sport, the Mercedes C-Class isn't a cheap car. This junior executive saloon is the machine most choose if they don't want a BMW 3 Series but still want the kudos of premium German brand image and a quality interior.
Unfortunately, owners who have paid big fees for one of these cars will be disappointed to know that they do suffer some common problems, not least irritating electrical and sensor faults.
When problems start to pile up: when a car is 9 years and 5 months old
7. Mini Cooper
Mini car with maxi repair bill: The most common fault claim against a warranty is for clutch repairs, which cost £414 on average
Mini Cooper most common faults repaired under warranty
| Fault | Ave Cost of Repair | Yr(s) Most Affected |
|---|
| Clutch Faults | £414.00 | 2004 and 2007 |
| Gearbox Faults | £858.00 | 2002-2004 |
| Engine Faults | £858.00 | 2007 |
| Steering Faults | £540.00 | 2004 |
| Thermostat Faults | £240.00 | 2006/7 |
The iconic Mini has changed somewhat under BMW ownership in recent times, and it's become far more expensive to run as a result.
Long gone are the days of cheap repairs and quick fixes - when something goes wrong with a Mini these days the garage receipts can sometimes be maxi.
All five of the most common claims for repairs are over £200 to fix, with major issues such as clutch, engine and gearbox fixes at the top of the list.
When problems start to pile up: when a car is 1 years and 6 months old
8. Seat Ibiza
You might need to take a Seat when you see the repair costs: The Ibiza might be a small and affordable car to buy second hand, but models start to encounter expensive issues after less than a decade of ownership
Seat Ibiza most common faults repaired under warranty
| Fault | Ave Cost of Repair | Yr(s) Most Affected |
|---|
| Engine Faults | £840.00 | 2009 |
| Electrical Faults | £840.00 | 2009 |
| Ignition Coil | £138.00 | 2006 |
| Turbo Faults | £684.00 | 2010/11 |
| Gearbox Faults | £840.00 | 2007 |
Seat's Ibiza is the Spanish brand's answer to the VW Polo and Skoda Fabia - and uses pretty much all the same underpinnings.
However, it seems to be much less reliable.
So you might think it's inexpensive to repair, given there should be plenty of spare parts kicking around, right? Not exactly.
Warranty Wise have it listed as the eighth most unreliable car based on the frequency of repairs and how much they cost. Topping the list is engine faults, which cost £840 on average to rectify.
When problems start to pile up: when a car is 9 years and 3 months old
9. Fiat 500
Fiat 500 with a common fault costing £744 to repair: If you own an older one of these you certainly won't want to encounter any gearbox issues looking at the cost of repairing them
Fiat 500 most common faults repaired under warranty
| Fault | Ave Cost of Repair | Yr(s) Most Affected |
|---|
| Gearbox Faults | £744.00 | 2009/10 |
| Suspension Faults | £300.00 | 2012 |
| Electrical Faults | £360.00 | 2010/11 |
| Clutch Faults | £288.00 | 2008 |
| Brake Faults | £192.00 | 2008-2010 |
Like the Mini Cooper, the Cinquecento is a retro small car from yesteryear that's now back on the market, be it in a heavily modernised format.
Still, it should represent affordable driving, but the dinky Italian city car has managed to squeeze into the rankings of the models most likely to encounter pricey problems.
Gearbox, suspension and electric faults top the list of issues owners made claims against their used-vehicle warranty for, which cost Warranty Wise an average of £744, £300 and £360 to put right on average respectively.
When problems start to pile up: when a car is 7 years and 7 months old
10. Renault Clio
Va va voom, goes your bank account: You might think an ageing used Clio would be cheap to run, but Warranty Wise data shows it could be a money pit
Renault Clio most common faults repaired under warranty
| Fault | Ave Cost of Repair | Yr(s) Most Affected |
|---|
| Electrical Faults | £216.00 | 2007 |
| Ignition Coil | £126.00 | 2006 |
| Suspension Faults | £198.00 | 2006 |
| Clutch Faults | £516.00 | 2006 |
| Gearbox Faults | £672.00 | 2002 |
This Clio might be a little long in the tooth by today's standards, but there are still plenty of them on the road in the UK today. That might be because drivers are tempted by the low second-hand prices - but they do need to buy with caution.
That's because Warranty Wise data ranks it as the tenth most unreliable used car.
Fortunately, the three most common faults - electrical, ignition and suspension related - are not outrageously expensive to fix, but others certainly are.
When problems start to pile up: when a car is 10 years and 7 months old
What are the most reliable used cars?
Now we've hit you with the list of the least dependable motors, what about the ones you can rely on?
Warranty Wise has given us the details of the 10 cars it receives the fewest warranty claims about.
These are the ones to consider buying...
1. Volkswagen Polo
2. Ford Fiesta
3. Ford Focus
4. Ford Transit
5. Audi A3
6. Audi A4
7. Vauxhall Corsa
8. BMW 3 Series
9. Nissan Qashqai
10. BMW 1 Series
What are the most and least reliable car brand?
MOST RELIABLE
1. Honda - 89% reliability rating
2. Toyota - 88% reliability rating
3. Skoda - 85% reliability rating
4. Mazda - 85% reliability rating
5. Fiat - 85% reliability rating
6. Renault - 84% reliability rating
7. Ford - 82% reliability rating
8. Volkswagen - 82% reliability rating
9. Nissan - 82% reliability rating
10. Audi - 80% reliability rating
LEAST RELIABLE
Land Rover - 65% reliability rating
Jaguar - 73% reliability rating
Volvo - 74% reliability rating
BMW - 75% reliability rating
Vauxhall - 77% reliability rating
Mini - 78% reliability rating
Mercedes - 78% reliability rating
Citroen - 79% reliability rating
Peugeot - 79% reliability rating
Seat - 79% reliability rating
