Welcome back to What could possibly go wrong, our series looking at the tempting but potentially disastrous used cars. These are the high-end, high-risk cars that once sat in the upper echelons of a manufacturer’s lineup and now command rock-bottom prices. Premium? Absolutely. Problematic? Almost certainly.
This week I’m exploring what could be the ultimate used Q-car. If you’ve not come across this term before, a Q-car – or sleeper in the US – is a performance car that doesn’t look like a performance car. It’s a understated car that doesn’t scream about its sporting prowess with muscular bulges, racing stripes and wings so big they could double as standing desks.
Sensible but hiding a very special engine
So why is it here? A 5.2-litre V10 that produces 423hp mated to Audi’s excellent Quattro all-wheel drive system should do it. This is the Audi S6, the quietly quick version that nowadays is the cheapest ticket to V10 ownership. For that reason alone it's cool.
You’d be hard pressed to notice it’s got a similar engine layout and size to a supercar from looking at it though. A discreet V10 badge, quad exhausts and some glitzy LED lights are as much as you’ll get. The interior is well-equipped and should be holding up well with age. Expect some dated technology though.
It wasn’t that fast for a V10 – 0-62mph is 5.2 seconds – so its big block rivals in the form of the Mercedes-Benz E55 AMG and BMW M5 aren’t a totally fair comparison points. For these look at the much more potent Audi RS6 uses a different V10 and is a more obvious performance car. Prices are more than double the S6 though.
Instead look at a E60 generation BMW 550i or W211 Mercedes-Benz E500 as the closest alternatives to the S6. Both are sensible-looking executive cars with big engines wedged under the bonnet but neither have the majesty afforded by the S6, they’re both ‘only’ V8s.
Alternatively, a last-gen Skoda Superb can make for a more dependable and sensible sleeper. The fastest 2.0-litre TSI mated to an AWD system may only produce 272hp, but it’ll beat the S6 to 62mph. It's not fun to drive, but in Laurin + Klement spec it’ll be sumptuously equipped and an excellent cruiser.
The biggest concern with the S6 is part availability. The S6 wasn’t a bestseller, and parts availability isn’t anywhere near as good as the Porsche Cayenne I covered last week. While I was able to find spark plugs, filters and other consumables for the S6, there wasn’t a handy service kit I could find in any nook of the internet. Spark plugs cost £170 for all 10, while filters will set you back between £20-30. Larger items are more of a potluck, brake discs for example are £230 for a twin set – if you can find them in stock.
Amazingly, Audi will offer an extended warranty on a used S6. You’ll need to find an example with less than 100,000 miles on the clock and it’ll set you back £1,929 per year, but the cover provides Audi-approved repairs and the guarantee of genuine Audi parts. That peace of mind almost sounds logical until you remember how little an S6 can be bought for.
To find out more, read our full Audi S6 (2006-2011) review
Pros
- It has a big V10 that sounds amazing
- Quattro AWD for added security
- It's well-built from quality parts
Cons
- It has a big V10 that's a pain to work on
- It's not as fast as you may think
FAQs: what you need to know about a used Audi S6
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How much does a used Audi S6 cost?
I’ve seen ropey examples for as little as £3,250; that’s phenomenal value for the engine alone. Don’t bother at this price though, the cost to get it into a roadworthy condition will be at least what you paid for it. Clean examples with a full service history can command close to £10,000.
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How much did an Audi S6 cost new?
According to our records the Audi S6 retailed for between £55,455 - £60,945 across its production run. Naturally there were plenty of optional extras available, including a Bose sound system, carbon fibre trim and Alcantara trim bits.
How to buy a used Audi S6
Decided that you need a V10 Audi in your life? Look at these five troublesome spots:
1 – Cooling system
That big V10 generates quite a bit of heat and adequate cooling is essential. Worryingly, the radiator, coolant hoses and water pump are known to be weak. Inspect the car for any sign of coolant leaks and keep an eye on the temperature on the test drive.
2 – Timing chain
The S6 uses four timing chains and they’re all mounted at the rear of the engine, and while the chains are dependable, the plastic mounts are known to break with age, potentially causing engine-ruining damage.
Stuffing a big V10 into an executive saloon does present another issue, namely access. It’s usually a hefty job replacing a timing chain, but the Audi’s complexity and labour-intensive serves to make it more expensive.
3 – Oil consumption
Oil consumption is notable on the S6, even for lower mileage examples. This can often be attributed to worn piston rings or valve stem seas. The oil also needs changing every 10,000 miles or 12 months.
4 – Suspension
The S6 could be optioned with adaptive suspension which partially helped smooth out the unforgiving ride, but adds yet another layer of complexity to contend with. Worn control arms, leaking air struts, and broken compressors comes with big repair bills.
5 – Fuel injectors
The Audi S6 features direct fuel injection and they’re prone to leaking and becoming clogged with carbon deposits. Symptoms include rough idling, loss of power, and poor fuel economy. There are 10 to replace too, which is an expensive job.
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