awdinut

by that I mean the oil cooler $$$ coolant leak where the engine has to get removed. And do the 6.0 engines develop the dreaded T-chain tensioner failures of the '07-'10 4.2s ?

MP4.2+6.0

No on both AFAIK. I have never heard or read of a case of chain issues on a W12. Also remember there was a predecessor W12 motor in D2's in Europe so the core design has been around some time, a good amount longer than the 4.2FSI w/ chains. Also W12 is port rather than FSI so none of the carbon concerns of FSI 4.2's or S8's. That has really been the bigger gripe with FSI. Also the chain issue is more with the earliest 4.2's used in other bodies. It is not "one size (problem) fits all." Specifically, it has not been tied to a D3 4.2 on this board AFAIK even after several debates, and meanwhile we have seen a few port 4.2 inter cam chain tensioner issues lately.

To round it out for you motor wise and condensing my 100K of experience with it and following since 2007, W12 core motor oddity troubles are relatively few. They are generally known among the experienced hands with them, a fair number of whom are on this board both in the U.S. and Europe. The tricks and fixes are typically known and often documented in some fashion.

• The cooling sensor is the most notorious. Back of (U.S.) driver's side head. Several of us have now proven out it can be done with what becomes a pretty simple intake manifold pull and then (barely) reaching in. Audi/Bentley say it is a "step 1, pull motor" but flatly not true; a few folks early on paid for that or had it done that way via warranty. Did mine at about 100K in a few hours with simple tools. By about 100K seems a common failure point.
  
• O2 sensor wiring can get flaky on first few years. It's on the car harness side, not the sensor. Fix is a new plug and some replacement terminal wires, which dealer sells. Easy project if you know the TSB trick. Did two of mine. Connectors are up on top by passenger side air box, so no difficult access issue. BTW, ALL four forward O2 sensors are accessible underhood, contrary to (false) internet myths. Actually meaningfully easier to get to than the buried 4.2's. The behind cat W12 ones are the drop motor ones, but few reports of issues there.
  
• Torque (motor) mount has been found by several of us to fail. But it does on the other motors too. First time it is done gets into drilling a one time hole to pull a bolt, which takes a lot of time. Mine was done by dealer under CPO.
  
• Small coolant line that runs from coolant reservoir behind motor gets brittle with time, and one toward front of motor the same though somewhat longer lived. A number of us have had that. Straight forward underhood stuff with a pair of pliers and screwdriver type stuff.
  
• Oil vapor lines from intake area to valve covers can crack as they get old and heat soaked, particularly when you pull intake to either do spark plugs or get at things like the sensor or thermostat. Easy to change, just cost more than you would think for plastic; dealer only. 4.2's actually have the same lines (except 2 not 4), but you don't tend to disturb them much on a 4.2.
  
• Occasional failure of a small inline thermostat buried with a tranny cooler underneath. Not well known, though I have documented in past for a fellow W12er. Results in somewhat colder running in really tough way below freezing/arctic type winter situations. Easy to access if you know it's there, and part sold standalone if you have #s--shown in S8 listings--same set up there. More importantly, the main thermostat (a more modern MAP controlled fast response one) is light years more accessible than the belt 4.2, basically directly under the intake.
• Air boxes are finnicky (same as S8), and the drivers side box has a hose buried underneath where you need to learn trick if you have pull it fully. Power steering reservoir is buried in front of it, again like S8's.
  

And on the missing: no timing belt. Yay!!!! So nice post my 4.2 to just not sweat that at all. Typical serp belt, but unremarkable there. Detail point, but unlike 4.2 there seem to be very few mystery SAI issues with the W12, which can be frustrating to diagnose with 4.2s and older V6's. The W12 does not have the trickier combi valves that the V8's and V6's did. Easy to access oil filter and canister (if you pull belly pan); easier than 4.2's and stares you right in the face, 13 quarts and all...

awdinut

Thank you so much for that one-stop-answer to all questions W12 from THE W12 guru...even ones I didnt know enough to ask !! Doesnt sound like there is any downside; actually get rid of some problems of 4.2 cars for a sum total reduction of potential expense it would seem. And 50% more power. Seems like a no-brainer.

The hard part will be to find an affordable W12 in the right color combo...but I am now committed to the search.

MP4.2+6.0

You're welcome. I edited a bit BTW if you skim again.

W12 downside once you know tricks is often the same as 4.2 with the more typical weak spots and maintenance--control arms, air ride, trunk motor, power control system oddities, 6 years on (factory) TPMS, solar roof HVAC blowers, occasional comfort close items, MMI screen gears, etc. Since W12's start no older than 2005, they probably avoid a lot of the shake down new model incremental issues of the 2004's. You do want to do your own work though--or have a trusted reasonable indy--to keep costs in check.

Unusual combo of uniqueness--a lot lower volume than R8 actually and lower than many other "exotics," yet most parts are pretty std. D3 and not differentially priced either if you are already used to Audi pricing in general. Several of the items in my list come down to some incremental heat soak underhood and some known plastics items. It will also cost something like 3 or 4 MPG's (and a notch up for insurance category), but gas is cheaper these days. Instant no excuses torque and smoothness like no tomorrow is the big smile factor every time. That never gets old! Do keep in mind on any D3, and certainly of the 2005/6 era, you want to be careful and realistic on those oft attention areas like control arms, trunk function, TPMS condition, brakes, etc. 80-90% of what I do maintenance or repair wise is straight "D3" rather than really W12 specific. Having had the 4.2 in my C5, there were some there too, headlined of course by the belt drive but then also other soft spots like the intake Rube Goldberg stage vacuum set up and the combi valve/vacuum hose/SAI once in a while puzzles.

BTW, I saw your W12 spec. Thought about raising my hand. Obviously I am long term committed to brand and A8/S8, but might move to very late high end D4 (S8/W12) as those ride down price curve. But torn with having mine well sorted, fully paid, up to date and I know it well. I still think D3 is the more timeless of the two and D4's have a lot of depreciation pain still to go. Mine is black w/ Amaretto, so it fails your outside color. It has all of rest of spec. You didn't mention extended leather BTW if I remember right. You have it in your D3 now I think but even on W12's, it was technically an option. Many/most probably have it. Brilliant black is the most common W12 exterior color (later years also had a metallic), and probably the hardest part of your spec. A fair number are black inside too. Maybe ACC on earlier ones like you are considering is challenging to find. Absolute total available pool is only in the hundreds per model year sold in the whole country. More than a few have been totaled by now as well (S8 is more the one way up there on repair cost and total type stats). It is also subtle even on this board, but the ratio of W12'ers who post here compared to total W12's in the wild might be 10-50x the same ratio for 4.2's. Makes them seem not so rare, but in the wild they definitely are. Even knowing exactly how to spot them, I rarely saw one even 5-8 years ago, let alone now, and that's in the high wealth areas of Silicon Valley. CA was/is second biggest market for them when new, with FL geezers taking the top spot.

Around here when they had some traction (pre the way higher volume S8's, the market crash, the GL fad, the Maserati micro fad, the Tesla fad, etc.), there was another local silver one around the area, and I think even a gold or grey one. But the various colors are not that common in the mix. On D4's in both W12 and S8 meantime, black on black are common, which just does not warm my heart. Silver and grey's in S8 exteriors in fair numbers, but usually black inside. Thus my own search is probably extended save for one recent S8 high end interior package I like that harkens back some to the Amaretto style and nice look.

awdinut

Talk about rare:I checked the Manheim Market report to see what 2005 W12s have sold for wholesale and saw that in Oct at the Riverside auction a WHITE W12 was sold ! Wish I had this idea sooner, although I dont know the interior color. And for some unknown reason nobody seems to have ordered Amaretto for a white A8...that would be stunning and seem so much more an obvious choice than the Light Beige.

MP4.2+6.0

Just pulled my W12 guides from back in those first two years. ...You did not miss your once in a lifetime opportunity a few months back... The two colors Amaretto does NOT come with in either 2005 or 2006 were Akoya Silver Metallic and...Arctic White. White ones came only with black, platinum or beige interiors per the Audi W12 internal dealer documentation. It did come with "Light Silver Metallic" though, as distinguished from the Akoya silver one.

As I thought, full extended leather, plus the rear fridge and the polished forged 20's were all "sold order" options only. In colors, Night Blue, Oyster Grey and Cambridge Green were also all sold orders only, so they will probably be rarer. FWIW, I don't remember many white W12's in general; its a more common D4 color than D3 I think. Also subtle as I dust off the old knowledge, but the 2006's have a better adaptive HID set up--2005's were basically a cornering light add on, while 2006 has what you think of as current adaptive with true swiveling optical assemblies, and they have dedicated cornering lights. 2006's also had the halfway in between graphical parking sensor MMI display until they got to the rear camera in 2007 (one of the very few 2007 differences). If you don't know, the 2005's (uniquely) can always be spotted by the W12 logos on the rear door trim. They moved to the front fenders for W12's from 2006 forward, the same as most any optional motor Audi even today.

carl viking

MP - not so sure on this one. Mine is '07 and I have the "dumb down version", no swiweling there!

MP4.2+6.0

[QUOTE=carl viking;24762279]MP - not so sure on this one. Mine is '07 and I have the "dumb down version", no swiweling there![/QUOTE

Maybe yours needs a fixin'... My 2006 (built in Spring 2005) swivels for sure. If I cut the wheel left and right on a quiet dark street, I can easily see the lights sweep yet more quickly from one side to the other. Same as my 2013 Q5 with it. The underlying documentation/explanation is in the 2006 inside dealer literature.

carl viking

[QUOTE=MP4.2+6.0;24762289]MP - I bet you a dollar mine don't swiwel! Have it on our Volvo and it's easy to see.
It may be broken though!....
So you have swiwel AND extra side light or just swiwel?
I definitely have the dedicated light bulb that turns on when you turn the wheel or turn on turn signal under a certain speed.
Zero codes on that - ever. Should't / would't that likely throw a code?

Yes - four seater AND ski sack is what the kids wanted. Probably my first choice as well, except that my kids are still a bit too young to fully appreciate the feature!!

On Monday I will check the sales brochure for my model year that I have and see what it says.

TSHong

My 09, swivels with steering where as my 05 did not. It works well when you are driving on roads but it's distracting in parking lots for me.