Models · Audi
Audi RS4 B7 buying guide
The B7 RS4 was built from 2006 to 2008 as a saloon, Avant and cabriolet, with a high-revving 4.2 litre FSI V8, a 6-speed manual and quattro four-wheel drive. Its known faults are well understood, and most have a clear check you can do at the viewing.
The versions
- 4.2 FSI V8 (BNS), 420PS
- 6-speed Getrag manual only, with no automatic offered
- Permanent quattro four-wheel drive with a Torsen centre differential
- Saloon, Avant and cabriolet bodies
What to check on a B7 RS4
3 model-specific things to look at when you view one. They're a starting point, not the full inspection.
Dynamic Ride Control dampers
What to look for: Turn the steering onto full lock and use a torch to look at the damper behind each front wheel, then at the rears. The DRC units have thin fluid lines running away from them. Each should be dry along its body. An oil film running down from the top, often with dust stuck to it, means a unit is leaking. On a rough road, the car should feel firm but settled, not knocking or vague.
Why it matters: DRC links each front damper hydraulically to the diagonally opposite rear one to control roll and pitch. The units can lose pressure and leak, common enough that Audi UK extended cover at the time. Many cars have had replacement sets, and some owners have converted to conventional coilovers, which is a recognised alternative.
Timing chain rattle on cold start
What to look for: Stand near the windscreen, where the engine meets the bulkhead, and have someone start the car from stone cold. A brief rattle for up to about three seconds is normal on this engine. A rattle that lasts longer, or comes back on a warm restart, is the thing to note.
Why it matters: The chains sit at the back of the engine, and their tensioners rely on oil pressure, which takes a moment to build on start-up. A longer rattle means the tensioners aren't holding. Wear is reported from around 80,000 miles, mainly on cars with infrequent oil changes, and replacement means removing the engine. Annual oil changes in the history are the best evidence against it.
Carbon build-up on the inlet valves
What to look for: On the drive, take the engine through the upper half of its rev range in a low gear. It should pull harder and harder towards the limiter. A car that feels flat in the mid-range and tails off at the top may have heavy carbon. Look in the history for an invoice naming walnut blasting, with a mileage.
Why it matters: Direct injection means fuel never washes over the inlet valves, so carbon builds up on them from new and restricts airflow. Badly affected cars have been measured well down on power. Cleaning the eight ports by walnut blasting restores it; chemical cleaning is reported to be much less effective.
Also in the full guide
- The oil cooler in the front grille
- The oil filler cap test
- Cracks in the drilled front discs
- Exhaust flaps
- The cold start, test drive and paperwork checks for the exact version you're viewing
The full guide to the B7 RS4
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
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.