VytautasV

Here's the thing, there is a low milage S8 D3 not too far away from me.
Currently I own a 2009 A8 D3 3.0 TDI for a year and a half now and I still keep turning back at it daily after I park it. Honestly after all the horror stories I heard about owning D3 A8 or any A8, just stayed stories. Obviously I own VCDS and check the car once a month or so, do regular servicing and yes there are some small things exclusive for Audi A8 that had to be fixed, but honestly it's all worth it.

I see a lot of people in this forum drive S8 D3 or used to drive one. I would be really thankful if you could tell me about maintenance, fuel milage and reliability of S8 D3, maybe even talk me out of it or encourage buying it.

Thanks and Happy Holidays!

Panelhead

The increase in torque and HP will be a big plus. I really wanted a S8 when looking back in 2013. All the ones I found were close to 40K.
Glad I settled on an A8 with short wheelbase. If all is right the 4.2 V8 has plenty of power for me and lighter engine helps with the weight distribution. still front heavy though.
The maintenance on the V-10 is a degree more difficult. As D3 age this is more relevant.
Without knowing the MY and mileage of the one you have spotted it is hard to guess. But if 12 - 15 years old an engine out for service will be in the cards if used as a daily driver.
My A8 suffered from failed coil packs in the first year I had it. First good problem to be diagnosed by VCDS. Dug in and refreshed plugs and all coil packs. Had a recall sticker but dealer had only replaced three of the defective originals. Houston summer heat and traffic killed a couple more. Quickly.
I have read this is not such an easy job on a S8. I was very apprehensive plus no master mechanic and did plugs and coils in an afternoon.
There are sensors and and the oil pan gasket that will require pulling the engine. I have read that changing plugs while the engine is out is time and money well spent.

BASARAB

Intake manifold, carbon cleaning and few leaking oil gaskets. Thats pretty much all the different work you will need to do compare to an A8. I took one to 150k miles before I sold it. Very reliable engine.
Due to the age, I would advice dropping the engine and change all the old gaskets and old hoses all at once, will save you lots of time trying to chase another oil leak

gbmarc

Having had a couple of S8's, currently with a 2009 and my daughter has the short wheelbase 2007 A8 here's my take on it:
The fuel consumption is much lower on the S8. I only get 13 to 14mpg (US gallons) in regular around town driving.
Driving across the States between 60 and 90mph I averaged only 18 to 19mpg. Compare this to the A8 where I get 17 around town and 24 -25 on longer trips.
One of my early 2007 S8's seemed to have a rougher ride than the A8 but my current S8 has a delightful smooth quiet ride. Not quite sure what made the difference as I tried them both on all the different suspension settings.
Both cars have been very reliable. The suspension air bags have failed on both of them and the air compressor on the S8.
Both have leaky camshaft cradles that slowly fill up the spark plug holes with oil. But it's not a huge deal to live with.
Both electric trunk openers are very fragile. I added new trunk shocks and the updated bump stops with internal springs which helps a little.
The power on the S8 is very cool as are the paddle shifters. My A8 has the paddle shifters too but I think you need the sport option to have them included.
I like the adaptive cruise control but not all the S8's have it. Sometimes the sensor at the front goes bad.
The 2009 S8 has a much nicer under engine belly pan with better attachments.
Spark plug and coil pack replacement is about the same difficulty on both.
Inlet manifold removal and decarboning I have only done on the A8 and it's not that difficult to do.
The inlet manifold internal flaps will break at some time and can't be fixed so you either have to live without them or spend large amounts of money.
I've driven the S8 with and without broken flaps and with the flaps is just smoother and feels nicer.
I really don't often rev the motor up there because I'm always paranoid that something expensive will break!!
The S8 has an elaborate exhaust with flex exhaust pipes but they are relatively easy to get re-welded when they rust out.
The S8 seats are more snug but my daughter's A8 has the heated and cooled seats which are nice too.
I've enjoyed both. The S8 holds its value better because it's rarer and I guess the V10 engine sounds exotic.
That's all I can think of for now.
Mark

Veikra

The added power isnt all, the gear ratio is way different. So that 100hp feels a lot stronger. That's a reason why the S8 is a lot thirstier than my a8l despite being lighter.

Greg5OH

If you are interested, my 2008 S8 will be for sale shortly, after the dealer replaced the sunroof the allegedly fixed under the recall. Going on BaT then.
Located in MI 114k miles, 2 owners. silver on black, extended leather, convenience package. $22k USD.

Engine out all seals replaced (rear coolant head tubes, cam carrier to head seal, both mains, oil cooler etc etc), custom 3" stainless exhaust, 200cell magnaflow cats, JHM tune, brand new ZImmerman/akebono brakes, filters up to date, brand new Conti DWS06+ tires all around, fresh alignment from Audi, wheel bolt to stud conversion, carbon clean, updated intake manifold, injectors cleaned flow tested and resealed, valley and front end resealed, right rear EPB, vacuum hoses front running lights and fog lamps, strut bushings, front sway bar bushings, FUCA bushings. Plugs ,coils trans filter and fluid within last 30k miles.

All my engine remove replace reseal videos are available on youtube. Maintenance log for every service performed, receipts for majority of parts that were bought online.
Needs nothing, no leaks, get in and drive cross country.

Ill offer 6 months free diagnostic support via email. Any questions you have about the car, email me.

The cars can be maintenance intensive and the lack of space in the engine bay means either engine out, or front end off.
Most you see for sale around the 10-12k mark will require another 10-15k worth of work to bring them to useable condition.

https://www.youtube.com/playlist?lis...HwdZ2qN_ffZTVn