Audi, A6, C4, S6 4.2 Avant Plus (1996-) Common Issues
1. Oil leaks from the rear main seal or valve cover gasket
Occurrence: 20%Cost to repair: $700Symptoms:
Engine oil staining on the ground, undercarriage or rear subframe, blue smoke from the exhaust.
2. Faulty or failing water pump
Occurrence: 15%Cost to repair: $900Symptoms:
Coolant leaks, overheating engine, low coolant levels.
3. Transmission problems (DCT) such as faulty sensors, solenoids, or clutch packs
Occurrence: 12%Cost to repair: $1200Symptoms:
Unusual noises, slipping, hesitation when shifting gears, or failure to engage into a gear.
4. Rear differential and axle issues
Occurrence: 10%Cost to repair: $800Symptoms:
Clunking, grinding, or whining noises from the rear of the car, vibrations while driving.
5. Faulty or failing engine mounts
Occurrence: 9%Cost to repair: $400Symptoms:
Engine vibration, clunking noise when starting the engine, or when accelerating.
6. Problems with the Audi S-tronic transmission
Occurrence: 8%Cost to repair: $1100Symptoms:
Unusual noises, slipping, hesitation when shifting gears, or failure to engage into a gear.
7. Faulty or failing ABS sensors
Occurrence: 7%Cost to repair: $500Symptoms:
Service brake assist warning light illuminated on the dashboard, unusual vibrations while braking.
8. Rear subframe and lower control arm issues
Occurrence: 6%Cost to repair: $600Symptoms:
Clunking noise from the rear of the car when driving over bumps or potholes, loose wheel bearings.
9. Faulty or failing S6/V8 engine electronics (e.g. MAF sensor, spark plug wires)
Occurrence: 5%Cost to repair: $900Symptoms:
Check Engine light illuminated on the dashboard, unusual engine performance, poor fuel economy.
10. Front and rear sway bar links issues
Occurrence: 4%Cost to repair: $300Symptoms:
Clunking noise from the front or rear of the car when driving over bumps or potholes.