MP4.2+6.0

Cost varies depending on whether you just do belt only, or preemptively do water pump, thermostat, coolant, rollers, tensioner and serp. belt. Parts costs vary too depending on whether you go dealer, OE equivalent/name brands, or unknown "cheap" package of the week. Many of us do either all of the dealer only parts, or a mix of the first two where the name brands are easy to find. Several have been burned on the initial "cheap" approach, and faux "German" or Euro sounding brand names may really be offshore junk of dubious origin if you don't know who's who among the OES's. Figure a guestimate $500-1500 as a broad range if you have it done, depending on indy vs. dealer, how many parts and related incremental labor, etc.

As noted, your target spec of 2006 and later picks up the 2006's as the last year w/ a timing belt in the 4.2's. By 2007 you get FSI w/ no more belt, a bit more power, to be balanced some occasional complaints about FSI fouling, and a rear back up camera. At 2008 you get the last major updates before the D4.

scottybooj

So, to be clear, this 2007 I'm looking at had a timing chain which is not an issue?

Thanks again to everyone. I'm psyched to get this in my garage already.

greginfinity

Correct, 2007+ model years in the USA use timing chains. The only gotcha with the chain is that it might stretch (not sure how chains stretch), or more likely the tensioners wear down or break causing the chain issues.

HOWEVER, I am not sure there is a single case of this on the D3 (search)? On other Audis with similar engines it does happen I believe.

MP4.2+6.0

Before 2007, it's a belt in the 4.2, but always chain(s) in W12 that went back to 2005 in USA.

RocketSurgeon

Lots of people with the S4 or A6 4.2 complain of chain issues, but those cars are much more prone to being driven hard. Perhaps that accounts for the difference. Those cars are also more common. It's just worrying that a timing chain overhaul is an engine out service $$$.

Vasco Spassov

Yes, chains do stretch! I found out when I bought a motorcycle, and after awhile had to re-tension the big-big (in comparison to a car engine's one) chain!
Maybe someone can tell us how exactly it happens!