Audi A8 - 3.0TDi or 4.2TDi

Ant84

Ant84

Ant84

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A few of you might have seen my last thread outlining my requirement for a car to use as a chauffeur/executive vehicle. After spending many hours researching and scouring the forums on the usual suspects (W221, F01, X350 etc) I've decided that, although it's a slightly more dated design, the D3 A8 is probably the best bet in terms of reliability.

My question is whether the 3.0 or the 4.2 diesel would be better for the purpose? Obviously the smaller engine will be slightly more economical but I've heard of a few (very expensive) timing tensioners failing on the 3.0, which seems to be less of an issue on the 4.2 lump. The bigger engine also falls into the higher tax band, but the sound from the V8 will be much less diesel like which might please customers a little more than the 3.0 would.

Looking for anything from 2007-2010 depending on spec. Doesn't seem to be that much different in the pre and post facelift circa 2008 so I'm not overly bothered about that.

Any owners or previous experience with these cars?
 
Yeah I've read all the articles and forum posts I can find. Suppose a few extra opinions from owners won't hurt.

I'll be doing quite a bit of driving in the car away from work too, so the prospect of a remapped 4.2TDi is great. That said, I'd hardly turn my nose up at a 3.0TDi if it was the only good example I could find.
 
The 4.2 sounds just as diesel-like at idle as the any other tdi lump.
The main issue with D3s is all the ancillary stuff rather than the engines. I had one a while back and it was shockingly unreliable. I bought it at 2 years old and sold it when it got to 3 due to the amount of stuff that had gone wrong with it.
I still think you're better off with a Lexus LS460 for this sort of game.
 
[TW]Fox;27150956 said:
Why would you remap a car used for this sort of work, pointless waste of money.
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As I just said, I'd be using the car an awful lot outside of work.

It's not like it would negatively affect the car when I'm driving it sedately for customers, just the enjoyment when I use it for pleasure is higher.
 
Rilot said:
The 4.2 sounds just as diesel-like at idle as the any other tdi lump.
The main issue with D3s is all the ancillary stuff rather than the engines. I had one a while back and it was shockingly unreliable. I bought it at 2 years old and sold it when it got to 3 due to the amount of stuff that had gone wrong with it.
I still think you're better off with a Lexus LS460 for this sort of game.
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Interesting. Which engine/year did you have?
 
I agree, I think you're massively over-thinking this.

99% of the customers won't be able to tell or give a damn whether it's a 3.0TDi or a 4.2TDi. Would you charge customers more for a 4.2? Would you hell, so buy whichever is cheapest to run. Business is about margins as I'm sure you know.

I'd go Lexus for this purpose too.
 
As above, I'd go Lexus and add a decent sequential LPG kit if fuel costs are an issue - it'll be by far the cheapest option to run, as well as not dag-dagging at idle.
 
Hi there,

Friend of mine has just purchased a 2011 4.2 A8. He had it remapped which took it to 400bhp and 1000nm. 41mpg on a motorway commute and that much power to boot makes it a no brainer in my opinion!

Kind Regards

Alec
 
3.0 litre if it was me. If I was the customer I frankly wouldn't care what was powering it providing it got me there comfortable and on time. The timing chain issue what I heard gives you warning that it needs replacing.
 
I have a 3.0 TDi 2006 D3. By 2007-2010 all the issues with piezo injectors and tensioners were fixed by production changes.
As with any car, late models were much better in terms of production improvements and reliability than early ones.
If I was you, I would take an A8L (LWB) and higher spec over 3.0 vs. 4.2.
e.g. ACC, Bang & Olufsen over BOSE, Rear adjustable heated and vented massage seats, rear seat entertainment and the extended rear console if you don't need 5 seats. Also rear electric blinds were not standard on all models (although I think they were from 2008)
 
Although I only had the 4.0tdi, it was pretty unreliable.. not the engine, just most other things. Nice cars but not worth the risk in my own opinion.

You really need to choose with the business hat on whatever you do. The 4.2 really doesn't make any sense above the 3.0 if its for a business. Youll get people mentioning power as above but that makes no sense here really.

I personally would look elsewhere anyway as they really are not the most reliable and more-so if you are doing greater miles I would think. The one I had was an early model but did they really improve that much over time?
 
Axeboy said:
I personally would look elsewhere anyway as they really are not the most reliable and more-so if you are doing greater miles I would think. The one I had was an early model but did they really improve that much over time?
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What did you have go wrong? I have the exact opposite experience.
I have had close to zero non-service/consumables failures after 8.5 years and 229,000 miles apart from with the engine which had a DPF, a turbocharger (caused by DPF back pressure) and set of injectors but I suppose even the DPF is a consumable.
The only other problem was a broken pin in the driver's door stowage box which was fixed with a self-tapping screw, and moisture/corrosion in an EPB connector which was fixed by soldering a new one onto the loom.
 
I think they must be a mixed bag with reliability. My mate had exactly the same experience as me and Axeboy in that pretty much everything ancillary went wrong. However, I know of people on this forum and others who swear by the D3 and have had 0 problems.
 
Went to look at a 3.0TDi LWB today and was pretty impressed.

Decided to drive half hour up the road to check out an LS460 SE-L since everyone kept saying that's what I should go for.

Bought the Lexus. It felt in a totally different league to the Audi.
 
Ant84 said:
Went to look at a 3.0TDi LWB today and was pretty impressed.

Decided to drive half hour up the road to check out an LS460 SE-L since everyone kept saying that's what I should go for.

Bought the Lexus. It felt in a totally different league to the Audi.
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Good man! Are you going to investigate LPG? Pics?
 
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