
Car dealers have lifted the bonnet on the used motors that they tend to avoid because either the engines and gearboxes are 'unreliable' or 'too expensive to repair'.
Industry experts told Car Dealer Magazine that certain cars, in their experience, can be a bad investment for both dealers and buyers.
Also speaking to Warrantywise, the UK-based provider of extended car warranties, admitted that there are a variety of whips that aren't worth the hefty repair costs.
According to the experts, problems with the engines, transmission, and gearboxes of these vehicles make them more likely to break down, which could potentially cost drivers thousands of pounds.
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And some of the cars affected are among the most popular brands.
In one instance, the engine is 162 percent more likely to break down than the average car.
Ford EcoBoost

At the top of the warning list is Ford’s EcoBoost engine, fitted to models including the Fiesta, Focus and B-Max. The engine uses a controversial 'wet belt' system, where the timing belt runs through engine oil instead of operating dry.
Mechanics claim the belts can deteriorate over time, potentially causing catastrophic engine damage.
Car YouTuber Lee Grant described wet belts as 'notorious for going wrong', while Warrantywise estimated the average EcoBoost repair bill at around £3,141.
Warrantywise admitted that the failure rate of the engines was potentially 'heightened by the sheer volume of Fords in the market'.
Ford told The Sun that it is 'confident in the robustness and reliability of its EcoBoost engine technology when the stated guidelines for maintenance and service are followed'.
They added: "Ford UK is happy to investigate service support and/or compensation measures for any customer who believes they have had an EcoBoost engine issue and is happy to review cases with a full-service history for vehicles up to ten years old with less than 150,000 miles.
"Any customers in the UK whose vehicle meets these parameters can contact Ford’s customer relationship team."
Mazda 2.2d

Mazda’s 2.2-litre diesel engine was also flagged by the experts. Found in the Mazda 3, Mazda 6 and CX-5, it has reportedly suffered from stretched timing chains, leaking injectors and clogged systems.
James Harding, of Chops Garage, said: "I love Mazda stuff. I find it, as a general rule, bulletproof reliable – but those Mazda 2.2s, my God, do they have issues.
"I’ve never seen engines that manage to coke themselves up as much as those Mazda 2.2s and that will throw an array of different warnings."
Warrantywise claimed the engine is twice as likely to fail as an average car.
Mazda told LADbible in a statement: "Mazda takes vehicle reliability extremely seriously and, where specific technical concerns have been identified, vehicles have been subject to recall or service actions. The Mazda 2.2-litre diesel engine was a popular engine in our product range and, like all modern Euro 5 and Euro 6 diesels, relies on emissions systems such as DPFs and EGR systems that are best suited to higher-mileage driving where regeneration cycles can complete correctly and correct maintenance and suitability to the owner’s driving needs are important factors.
"Industry-wide experience has shown that diesel vehicles used predominantly for short-distance or low-mileage driving can experience increased soot build-up and emissions-system related issues. The story appears to be based primarily on warranty claims data and individual trade opinion and can naturally overrepresent older, higher-mileage or poorly maintained vehicles."
PureTech engines

These cars, found in Peugeots, Citroëns and Vauxhalls, also tend to suffer from wet belt, with Warrantywise claiming that the failure rate on these engines is 31 percent more likely than the average car.
They noted that repair costs can be as much as £2,152.
Shifting Metal presenter and car dealer Joe Betty said: "They’ve got a plethora of problems. From the wet belt system, which either breaks or clogs the oil pickup and starves your engine of oil, completely ruining it, to the fact that this thing uses an absolute ton of oil.
"They’re a nightmare, and they’re probably going to come back and bite you."
Ford PowerShift gearboxes

Ford’s PowerShift automatic transmission - fitted to some Ford and Volvo models - was criticised for jerky changes, slipping and costly failures. Experts said repairs can easily exceed £2,300.
Theo Cook, of Bowen’s Garage and YouTube channel Ted Torques, said: "The Ford PowerShift automatic gearbox has to be one of the worst gearboxes ever invented in all of human history.
"A terrible gearbox that has no longevity, is extremely expensive to repair and causes a huge amount of problems."
CVT gearboxes

CVT automatic gearboxes, used by several manufacturers including Toyota, were also described as fragile and expensive.
Although smooth to drive, dealers warned they can be difficult to repair and costly to replace, with average bills nearing £3,000.
They noted that failure rates were about average, but dealers were more likely to encounter faulty CVT gearboxes because they're so common.
Jamie Caple, owner of car dealer Car Quay and the YouTube channel Car Lateral, claimed he 'avoids' vehicles with CVT gearboxes, explaining: "They fault, they’re very difficult to fix and are extremely expensive to replace."
JLR Ingenium engines

Finally, Jaguar Land Rover’s 2.0-litre Ingenium diesel engine was labelled the biggest risk of all.
Dealers claimed timing chain issues and internal failures can appear without warning. Warrantywise data suggested these engines are 162 percent more likely to fail than average, with repair costs exceeding £5,200.
Umesh Samani, chairman of the IMDA and a used car dealer, said: "The one on my list, the number one that I won’t buy, has got to be, sadly, the Land Rover Ingenium engine: the 2.0-litre diesel Ingenium. They just fall to bits for no apparent reason."
A spokesperson for JLR UK told LADbible: “Quality across the entire client ownership experience is a priority for JLR. Independent data shows that our overall vehicle quality is its strongest to date, and we continue to drive further improvements.
“JLR is committed to delivering the highest standards of quality and we work with a network of partners to deliver support and services reflective of our brands.
“In doing so, our clients are fully supported with warranties and service plans that protect them throughout ownership.
“Any clients with questions or concerns about their vehicle should contact their retailer or authorised repairer for support.”
LADbible Group has contacted the manufacturers for comment.