Serpentine belt diagram 05 audi a8 l - 2005 Audi A8

Question edited for clarity.
Question moved to model category

https://www.google.com/search?q=2001+A8+Quattro+4.2.+serpentine+belt+diagram

You have You Tube Video you can watch &
lots of diagrams & print to see & read,just
start using Google for all your questions

google serpentine belt diagram for a 2008 Audi TT 3.2
and select images for more info

copy and paste
https://www.audiworld.com/forums/a6-s6-c6-platform-discussion-58/3-2l-fsi-whats-wrong-belt-tensioner-how-replace-plus-serpentine-bel-2764904/

clean off the pulleys & then run round the edges with chalkm pool cue chalk is good, when you have done this the timing marks will be plainly visible

the timing marks are located on the pulleys , clean them off & then run around the pulleys with pool cue chalk, the timing marks are plainly visible after this little trick/tip.

2000 AUDI A8 4.2 L V8 engine serpentine belt routing diagram


CS = Crankshaft
F = Fan pulley
Gen = Alternator
G = Guide pulley
T = Tensioner pulley
AC = Air Conditioning
PAS = Power Assisted Steering

Every 60,000 miles. Change the timing belt, accessory serpentine belt, hydraulic timing tensioner, tensioner and idler rollers, tensioner relay arm, water pump, thermostat, and coolant. A dealer will charge you $1100 or more, and an independent European specialist probably $650-750. If you're in range of the southern tier of NY, I can do it for you (I specialize in Audi and VW). Order your parts online and I'll do the work for $250 in labor.

If it's anything like the six cylinder engines from Audi, which I'm very familiar with, and from what I remember of the V8, you have a timing belt that drives the water pump, crank, and exhaust cams, and also includes a tensioner and an idler roller. The timing chains come into play in the cylinder heads. What Audi did was to only drive the exhaust cams off of the crank, using the timing belt, and inside each cylinder head there is a timing chain assembly that is used to drive the intake cams off the exhaust cams. On a periodic service (like the timing service) you only need to do the timing belt. The timing chains are only replaced if the tensioners fail - you'll know this by a diesel-like clatter from the cylinder heads. Failure of the chain drive assemblies is very rare, which is good because they're incredibly expensive (on the V6 engines they're upwards of $700 each). If you're doing this job because it's due based on mileage, don't touch the timing chains in the cylinder heads - only change the timing belt, tensioner roller, relay arm, hydraulic tensioner, idler pulley, water pump, and serpentine belt. You can leave the chains alone.

autozone can print you out the correct belt routing and you can rent a serpentine belt tool to do the job right

relatively easy. just weave the belt over, under and around the pulleys the way its show on the belt patter on the label on the radiator., or make note before pukking off old one. Good luck. Watch the fingers!