Audi RS4
Facelift version of the 2.9 TFSI V6 BiTurbo with OPF and 48V mild hybrid — 450 PS like the DECA, but with particulate filter and BSG starter-generator. The OPF noticeably mutes the V6 sound; the mild hybrid delivers brief boost pulses during launch. The rocker arm bearing issues of the DECA also affect the DNXB — same design, same wear pattern on the exhaust camshaft rocker arm bearing. The water pump is a known weak point as with the DECA. Compared to the DECA: less emotional, but slightly more economical in everyday use through regeneration and coasting.
BiTurbo V6 replaces V8 — faster, wider, less soul
450 hp twin-turbo V6 replaces the NA V8. 0-60 in 4.1 seconds, wider than its predecessor, technically superior. But the sound doesn't touch the B7, and the auto-only gearbox leaves no room for manual nostalgia. The RS4 for people who rank lap times above goosebumps.
Engine Weaknesses 6
Design flaw: water pump leaks internally and draws coolant into the vacuum system. Can cause severe engine damage if not stopped immediately. Improved 6-bolt version available as replacement.
Symptoms: Coolant loss in expansion tank, fault codes P0299, drive interruption message, coolant deposits on engine block bank 1
Small bearing rollers on the rocker arms detach on early units (GP0-P code) and fall into the sump. Caught early, replacement costs a few thousand euros; undetected, total engine failure.
Symptoms: Ticking or knocking on cold start and at idle, engine warning light, metallic noise from cylinder head area
Two turbos in the V6 are exposed to severe heat. Insufficient warm-up and immediate shutdown after full load substantially accelerates bearing wear.
Symptoms: Whistling from turbo area, smoke from engine bay, power drop, increased oil consumption, blue smoke
The 2.9 TFSI V6 BiTurbo uses a cooled indirect charge-air system. Oil supply to both turbos is critical on cold start. Insufficient cool-down after hard use can damage turbo bearings.
Symptoms: Whirring after engine shutdown, smoke from exhaust on cold start after hard use
S-Tronic (PDK) on the RS4/RS5 B9 shows accelerated clutch wear with frequent track/sport use and launch control. Stop-and-go city driving makes it worse.
Symptoms: Juddering on pull-away, dual-clutch noises, gearbox control faults
Turbo direct-injection without port spray. Deposits build on intake valves with frequent short trips or skipped cleaning intervals.
Symptoms: Power loss under partial throttle, rough idle, increased fuel consumption, sluggish throttle response
Vehicle Weaknesses 7
Defective coolant valves cause coolant loss that can silently lead to overheating. Temperature sensors and thermostat housing are a weak point from 60,000–100,000 km.
The rubber bushings in the upper control arms wear prematurely, in some cases from as early as 60,000–80,000 km. The issue is said to have been fixed only with the 2019 facelift.
Certain 19-inch tyre combinations on the B9 lead to premature wear on the inner flanks. The cause is a suspension setup not optimally tuned for larger wheels. Regular wheel alignment recommended.
The S tronic dual-clutch gearbox judders when pulling away and at low speeds. The mechatronics unit can become defective.
Water pump and thermostat housing typically fail between 60,000 and 170,000 km. A well-known weak point on the 2.0 TFSI and 2.0 TDI.
The S tronic dual-clutch gearbox exhibits a known juddering in D and R at idle that Audi classes as within the state of the art. Diesel variants may additionally creep.
The MMI infotainment system frequently exhibits Bluetooth connectivity problems in facelift models: choppy music playback, missed ringtones. Software updates do not always provide a permanent fix.