The V10 engine is generally a rare beast, with only a few manufacturers ever developing them. Out of the cars that do sport these engines, most can be divided into one of two categories: V10s for hauling and V10s for performance. Hauling V10s are generally reliable and easy to fix, even if they guzzle gas like it's going out of style. But, it's the engines built for performance that can often turn out to be money pits.
Today, it's not difficult to find a V10-powered car at a reasonable used price, but often these cars come with hidden costs that the unsuspecting buyer might not be aware of. There can be any number of issues arising, from unreliability to costly parts or even previous owners abusing their cars. No matter what the reason, it's best to avoid these cheap used V10s as they might end up costing more to run than they do to buy.
8 Audi R8
The R8 has been Audi's flagship since production started in 2006, and today early models can be bought for a fraction of the retail price. The engine of the R8 is largely reported to be reliable, and even the earliest R8s still turn heads in the street. So what's the issue with buying one?
Well, with their attractive prices on the used market, it's easy to forget that buying one of these cars new will cost $142,700. Even the most depreciated used examples will still have servicing costs that match that of a $150k car. That means even one seemingly innocent trip to a garage can cost an owner thousands and quickly drain their bank account if they weren't expecting the hit.
7 BMW M5 E60
The E60 M5 sports the only V10 engine to ever be put into a production BMW, alongside its sister car the M6. It sounds amazing, and when it's all in working order, it's great to drive too. The problem is that it's horrendously unreliable, in fact, it has a reputation as one of the least reliable M cars ever.
The E60 suffers from a variety of problems including rod bearing failures, oil leaks, and throttle actuators. It's horrendously expensive to fix when it goes wrong, and it goes wrong a lot. It might be cheap on the used market, but as the old saying goes, if it looks too good to be true, it probably is.
6 Volkswagen Touareg TDI
The V10 in the Touareg SUV was built for smoothness and refined driving, as a competitor to the class-leading Range Rover. Unfortunately, like the Range Rover, the Touareg also suffers from a host of issues that make it very unreliable.
Not only do early Touaregs break on a regular basis, but thanks to their countless computer systems and complex construction, they're difficult to fix too. The problem has got so bad that some owners have reported sending their cars to the junkyard rather than paying the exorbitant costs to fix the VW's persistent issues.
5 Dodge Ram SRT-10
The Ram SRT-10 is an undoubtedly crazy truck, making 500 hp from its huge 8.3L V10 engine. By itself, it's fairly reliable, and it's not that difficult to fix when things go wrong. But, the problem comes when buying a used car with several previous owners. Given the age of the truck, it's difficult to find a cheap example that's just had one previous owner.
Most will have been through several pairs of hands since leaving the factory, which means it's very likely that at least one of those will have abused the truck to some degree. It's a 500-hp pickup, so the natural instinct for many drivers to pull some burnouts, but too much careless driving will have had a long-term impact on the overall condition of the truck's internals. So, if the new buyer isn't careful, they could end up with a long list of worn parts that need fixing and a financial headache on top.
4 Audi RS6 Avant C6
Audi's premier super-family car shares its V10 with the R8 supercar, and like the R8 it's not the engine that will cause the biggest problems for a buyer. It's instead all the other maintenance and servicing costs, although the C6 is actually one of the more reliable generations of the RS6.
That's not saying much though, as a 2013 survey by British insurer Warranty Direct put the RS6 Avant as the most unreliable car in Britain, one place below the E60 M5. With reliability stats like that, something major will inevitably go wrong sooner or later, and when it does, it'll cost a lot to get it put right.
3 Volkswagen Phaeton TDI
In what has to be one of VW's worst marketing decisions ever, the brand decided they wanted to make a Bentley but with a VW badge. The result is the Phaeton, which actually features a lot of parts borrowed from the Bentley Continental. But, to the average passerby, it looks no different from a regular VW Passat.
Why anyone would pay for one of these new is a mystery, but a few buyers did. The V10 engine is taken from the VW Touareg, and like the Touareg, it's expensive and unreliable. Unsurprisingly, VW pulled the Phaeton from sale after just two years in America.
2 Audi S8
Anyone looking for a depreciated luxury executive car should definitely consider an Audi S8, as it's one of the fastest depreciating cars of its kind. But, buyers should beware that it'll cost a fortune to keep running, probably more than the car is actually worth.
It's mainly thanks to the myriad gadgets and features that come with the S8, all of which often break after a few years. Cheap S8s often come with broken electronics, but even basic electric features like adjustable mirrors can run up eye-watering bills to fix.
1 BMW M6 E63
The counterpart to the E60 M5 is the E63/4 M6, as they share most of their internals and the same V10 engine. Unsurprisingly, like the M5, the M6 is prone to a lot of costly problems that'll likely ruin an owner's day when they inevitably break at the most inopportune time.
The upside of the M6 is that it's one of very few convertible V10 cars out there, alongside the Audi R8 and Dodge Viper. But, the M6 has neither the star power of the R8 nor the reasonable running costs of the Viper. So, it's best to stay well away from this Bavarian beast unless buyers have deep wallets.