Models · Audi
Audi A6 C6 and allroad buying guide
The C6 A6 was sold from 2004 to 2011, as a saloon from 2004 and an Avant from 2005, with a facelift in autumn 2008. Engines run from the 2.0 TDI to V6 and V8 petrols and V6 diesels, with front-wheel drive or quattro. It has a good reputation for reliability, and its known issues are specific to particular engines and gearboxes.
The versions
- Diesel: 2.0 TDI (140PS, 170PS from 2008), 2.0 TDIe (136PS, from 2008), 2.7 TDI V6 (180PS and 190PS) and 3.0 TDI V6 (224PS to 240PS)
- Petrol: 2.0 TFSI (170PS), 2.4 V6, 2.8 FSI V6 (replacing the 2.4 by late 2006), 3.2 FSI V6, 4.2 V8, and the 290PS 3.0 TFSI V6 from September 2008
- Multitronic CVT automatic on front-wheel-drive cars, Tiptronic torque converter automatic on quattro cars, or a manual
- quattro standard on the 3.0 TDI and the 4.2 V8, optional on mid-range engines
- Saloon, Avant and allroad quattro bodies (the S6 and RS6 have their own pages)
What to check on a C6 A6
3 model-specific things to look at when you view one. They're a starting point, not the full inspection.
Multitronic gearbox behaviour
What to look for: On a front-wheel-drive automatic, pull away gently several times from a standstill and feel for judder. Accelerate steadily and watch the rev counter for sudden flaring or rising and falling revs. Coast down to a stop and check the engine doesn't stall.
Why it matters: Front-wheel-drive automatics use the Multitronic, a continuously variable gearbox. Judder when pulling away and unsteady revs are the warning signs, and 2.0 TDI Multitronics can stall when the gearbox struggles with engine braking. Later cars are better, and a documented service history makes a big difference. quattro cars use a conventional Tiptronic automatic instead.
Timing chain rattle on V6 and V8 engines
What to look for: Ask for the engine to be completely cold when you arrive, and listen at the front and back of the engine for a rattle in the first seconds after starting.
Why it matters: The V6 and V8 engines in this generation drive their camshafts with chains. Worn tensioners and stretched chains can rattle on a cold start, earlier cars more often, and long oil change intervals and short trips make it more likely. A quiet cold start is the good sign, and invoices for chain work mean it has been dealt with.
Cambelt on the 2.0 TDI and 2.0 TFSI
What to look for: On a 2.0-litre car, look in the history for the last cambelt change, with its date and mileage.
Why it matters: The 2.0 TDI and 2.0 TFSI use a cambelt, due every five years or 75,000 miles, whichever comes first. The larger engines use chains instead. A car that's overdue needs the belt doing straight away.
Also in the full guide
- Diesel oil level and exhaust smoke
- Dual-mass flywheel on manual cars
- Air suspension ride height
- Avant tailgate and rear washer
- The cold start, test drive and paperwork checks for the exact version you're viewing
The full guide to the C6 A6
The CrankSight guide walks you round the car on your phone at the viewing, with every check for the exact version you're looking at: what to look for, where to find it, and what anything you find is likely to cost. As you go it builds an assessment of that car, and if you view more than one, it lines them up side by side.
£29 for the model, used on as many cars as you like, delivered within 72 hours or your money back.
Other generations
Audi A6 C5 and allroad · Audi A6 C7 and allroad · Audi A6 C8 and allroad
General points for the model, last checked October 2026. Every car is different, so treat this as a guide to what to look at, not a verdict on any car. CrankSight is independent and has no connection with Audi.