On a value for money basis, the 2006 Audi S8 could be one of the biggest bargains out there. For around £10,000, you get a 5.2-litre V10-powered sports saloon with all-wheel drive and enough space for a quartet of you to travel in complete luxury. It will also crack 0-62mph in 5.1 seconds before running into the electronic limiter at 155mph when the engine still has plenty to give.
Of course, you could look at it another way, and wonder why so much car is on offer for so little money… You don’t need a doctorate in Shedology to know expensive, fast saloons retain their appetite for large bills even when their age-adjusted price tumbles into the temptingly affordable bracket. So it is with the D3 generation of S8.
Much of this car’s appeal lies in its V10 engine, which is related to rather than borrowed wholesale from the Lamborghini Gallardo. In this guise, the V10 makes 450hp and 398lb ft, with the latter developed at 3500rpm to peak at half the revs of its distant Italian cousin. Rather than lament that, though, celebrate that it makes the S8 a superbly adept high speed cruiser. Average fuel economy of 20.3mpg might reign in the range to some degree, but there’s a 90-litre tank so you can still easily cover 350 miles before the warning light blinks at you.
You can also use the S8 year-round thanks to its Quattro four-wheel drive, supple ride – even though it sits 20mm lower than other A8s – and smooth six-speed auto. On top of that, every S8 is laden with leather upholstery, electrically adjusted seat with position memory, double glazing and pop-up infotainment screen. Popular options included a Bang and Olufsen stereo upgrade and you should look for S8s with parking sensors as it’s a big old bird.
Audi also offers carbon ceramic brakes as an expensive option, but few owners bothered ticking this box. The steel discs work fine and CCBs are now a wallet-melting liability if they need replacing.
During its four-year run, little changed with the S8 and it didn’t catch the imagination of many buyers. Now, it’s a fast, understated way to travel if you can stomach the occasional big bill. Reckon on spending from £10,000 for one with full history and 100,000 miles. A 60,000 miler will start at £16,000 and you should factor in the cost of an aftermarket warranty.
Aluminium bodywork resists corrosion, but look for signs of previous repairs. Any damage to the panels is expensive to put right.
Engine and transmission
Access to the rear-most spark plugs is limited and requires the engine to be partially lowered to remove them. This makes replacing all 10 with the correct plugs a pricey service item and explains why a major service from an independent garage can come to £750. Minor services are around £600.
Cam cover gaskets leak and let oil drip onto the exhaust manifolds, so look and smell for signs of this. Replacing this gasket is made trickier by the rear bolt being hidden under the bulkhead due to the length of the engine.
Another awkward job is replacing a faulty starter motor, which demands the engine be removed from the car. That will come to £4000 in labour charges.
The oil pump seal can fail, generally at around 100,000 miles, but with this generation of S8 getting older now it can strike on lower mileage examples. The seal is pennies to buy but requires the engine to be removed, though some specialists can do the job with the engine in situ to bring the labour cost down to around £1,500.
Coil packs can fail, so watch out for any rough running.
Transmission fluid changes at 20,000-mile intervals are recommended as the Tiptronic ‘box has to cope with a lot of torque and all-wheel drive traction. Listen for any noises from the gearbox and walk away if it there are, or if the shifts are not perfectly smooth.
Suspension and steering
The S8 weighs in at 1940kg, so the suspension gets a hard time. The front uses twin upper and lower wishbones, so there are double the number of bushes. Replacement suspension arms from Audi are £250, but good used replacements can be had for £125 from Prestige Motor Services.
Wheels, tyres and brakes
The standard brakes work well, but check their condition. New front discs and pads will set you back £850. Rear pads are around £100 per set.
Make sure the electronic handbrake is working efficiently. If not, it could be just worn pads, but if it’s an electrical fault it can cost up to £1000 to put right.