Currently reading: Used car buying guide: Audi RS6
Audi’s RS6 Avant weighs more than two tonnes but its V10 delivers a punch like few others. John Evans examines the estate that thinks it’s a supercar

They call it the ‘50p seal’ because that’s what it costs in your hand.

Unfortunately, fitted to an RS6, it costs considerably more – from around £2200 after you’ve taken parts and labour into account. It goes in the oil pump. When it fails, it allows oil to leak onto the driver’s side of the engine’s undertray. When checking over a used RS6, look for oil pooling there and weeping at the back of the engine.

See Audi RS6 for sale on PistonHeads

We might as well get that out of the way first. That and the car’s coolant pipes, which, where they run around the wheel arch, are exposed to the elements. In time, they rot and leak fluid. Some garages reckon it’s an engine-out job to fix but others are smarter and can do the work in situ for a fraction of the price. Either way, check these as well before you buy.

Rs6 2509

And while you’re at it, give the dynamic ride control (DRC) system the once-over. Its hydraulic dampers can leak fluid. Road dirt was blamed for damaging the seals and at one point Audi issued rubber covers to protect them. Check for leaks.

All well? Good because it would be a shame to allow these three well-documented, but mercifully rare, problems to slip through undetected, so spoiling the pleasure of owning one of the most rapid estate cars in existence. (There’s a saloon, too, but the Avant was easily the more popular.)

The RS6 – the C6-series model that ran for just two years, from 2008 to 2010 (it was mildly facelifted in 2009) – is powered by a 5.0-litre V10. It’s force-fed by an intercooler and two turbochargers to produce 572bhp – and 479lb ft torque from 1500rpm all the way to 6250rpm. Quattro four-wheel drive and a six-speed Tiptronic gearbox (so without the brutal launch control system found on some of Audi’s DSG-based S tronic gearboxes) are standard.

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Also standard is the aforementioned DRC suspension, a mechanical system that diagonally links the car’s front and rear wheels using hydraulic lines controlled by a central valve.

It’s supplemented with a three-stage variable damping system offering three ride settings: Comfort, Dynamic and Sport. Check it all works.

The RS6 rides on 20in alloy wheels and weighs a smidgen over 2000kg. The cabin must shoulder some of the blame for the car’s scale-crushing portliness. Climate control, a Bose sound system, electric front sports seats, heated front and rear seats, leather trim – you name it. Options included privacy glass, rear sunblinds and soft-close doors. A lot of RS6s have these and more.

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They also have a penchant for the hard stuff (expect around 17mpg) and an annual road tax bill of £535. No one said supercar-crushing performance was cheap.

Actually, when you consider prices for 2008-reg RS6s start at around £17,500, you could say exactly that. Check the suspension and the coolant system are sound, make sure you’ve got 50 pence in your back pocket for that oil pump seal, and have a go.

How to get one in your garage: 


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“I owned a limited-edition RS6 V10 Plus for four years. It had £8000 of options, if you include removing the speed limiter. It was a flying machine –not as raw as the earlier C5 RS6 I owned, but you could really press on. It was a heavy car and, in all honesty, it was a little numb but the four-wheel-drive system meant you could really use the power without getting in a tangle. As I speak, we’ve got four going through the workshop. Usual things: leaky oil pumps and intercoolers, and rusty coolant pipes. But the earliest are nine years old so it’s to be expected.”

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Buyer beware...

ENGINE - Oil changes are every 10,000 miles. Audi reckons the major service is every 60,000 but every 20,000 is recommended. Beware the dreaded ‘50p seal’ (see main story). The engine can take a Stage 1 or 2 power boost to 850bhp without strengthening but check the work has been done by a recognised workshop.

COOLANT SYSTEM - Where the coolant pipes run behind the driver’s side wing, they’re exposed to the elements and rust through as a consequence. Some garages claim it’s an expensive engine-out repair but it can be done in situ for around £500.

TRANSMISSION - Tiptronic ’box is tough but check the oil and filter have been changed every 40,000 miles. (It costs around £500.)

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SUSPENSION AND BRAKES - Standard hydraulic dynamic ride control (DRC) suspension can suffer leaky shock absorbers. Budget around £600 per corner for parts and labour. Check the suspension hoses linking the system diagonally corner to corner aren’t leaking too. Huge 390mm front brake discs are around £550 each, including pads. Check tyre life since premium rubber is about £250 a wheel.

BODY - Corrosion is unknown, so if you see any, suspect a crash repair. On that subject, check for uneven panel gaps.

INTERIOR - It’s tough but check everything works, including the DRC’s three settings.

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Also worth knowing:

Audi will sell you a warranty for your RS6 if it has done less than 100k miles and is unmodified, so buy a high-miler and beat the seller down to recover the warranty cost. As an example, named component cover on one 99,000-mile 2008/08 RS6 Avant with full Audi history is £1514 with a £250 excess. The car’s for sale at £21,000 but its trade value is £16,150 so, depending what it owes the dealer, you could haggle the warranty cost off the price.

How much to spend:

£17,500-£19,995 - The first 2008-reg RS6 Avants, and the odd 2009, from 90k to 120k miles.

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£20,000-£22,995 - More tidy 2008 and 2009 Avants with around 80k miles, such as a 2008/08 with 73k miles, full Audi service history and an AA warranty for £22,995.

£23,000-£24,995 - Ditto above but 2009-reg saloons with around 70k miles now in the mix, priced from £24,000.

£25,000-£29,995 - Mainly 2009-reg Avants with less than 50k miles plus some saloons, including a 39k-mile 2010-reg for £29,995.

One we found:

AUDI RS6 AVANT, 2008/08, 73K MILES, £22,000 One-owner RS6 with full Audi service history and black leather interior. Its auction value is around £17,750 so there’s surely scope for a discount. But given its rare and prized one-owner provenance, full Audi service history and low mileage, expect to fight for it. 

John Evans

Read more 

Audi RS6 review 

Audi RS4 review 

Audi R8 review 

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xxxx 24 January 2018

Running old'ish cars

I'm running an old'ish sports car at the moment and I reckon the trick is to buy a straight honest one privately, with no real corrosion and don't worry about the minor problems, these keep the price down and will give you something to do to make ownership interesting and rewarding.

Spend time and money on whatever it takes to get it 95% as quick as possible before you get disillusioned/fed up with constant DIY and garage bills then end up selling it on vowing never to do it again. 

Then once you've got them running right and all the little bits fixed you'll be surprized how fun it is run/maintain older cars, just remember all the money you spend on repairs is offset by little or no depreiciation.  


Pistachio 24 January 2018

Cheaper to run a Ferrari

I owned a quattro A6 non RS and it was soooo expensive to run, Tyres alone cost a fortune £7K in 8 years for tyres is no joke 

Dont get me wrong they are great cars, but ouch the bills !!

xxxx 24 January 2018

£900 a year on tyres

Pistachio wrote:

I owned a quattro A6 non RS and it was soooo expensive to run, Tyres alone cost a fortune £7K in 8 years for tyres is no joke 

Dont get me wrong they are great cars, but ouch the bills !!

Just out of interest size are they and how many miles do you do (£900 a year may not be as expensive as you think for such a big car AWD) , you never know you might get a few tips and recommendations.

Straff 24 January 2018


"What's that noise?? Is that a leak? - No, it's from the previous car parked here. I think. Is that a misfire? That sounds like a clunk! Is it down on power since I last drove it? HOW MUCH???" One for the (very) brave... Great car, though.