Audi A6
Supercharged V6 with 245 kW after facelift. Most powerful supercharger variant of the EA837 in A6/A7. Excellent long-distance engine.
333 hp supercharger in a touring palace
The most powerful supercharged variant in the A6 C7 turns the saloon into a real motorway sprinter. 333 hp and instant supercharger torque deliver a combination that satisfies even sporting drivers.
Engine Weaknesses 7
Coolant leakage into the integrated supercharger intercooler is particularly critical in the CTUA due to the higher boost pressure (245 kW) — hydraulic lock is possible.
Symptoms: Coolant loss, white exhaust cloud, cylinder 3 misfires, power loss.
EA837-typical: upper chain tensioners lose oil pressure at rest, brief rattle on cold start. The CTUA as the performance variant (S6) runs under higher thermal load.
Symptoms: Brief metallic rattle after cold start, gone after 1–2 seconds. With wear, permanent chain noise.
Coolant pump and thermostat fail at high mileages. S6/A7 3.0 TFSI at 245 kW places high demands on the cooling system.
Symptoms: Overheating warning, coolant loss, unstable temperature gauge.
The CTUA runs at 245 kW and permanently stresses the Eaton supercharger more than the 213 kW variant. The front nose bearing wears correspondingly earlier.
Symptoms: Rev-proportional whistling from the supercharger area, in extreme cases bearing failure.
The CTUA as the high-performance variant stresses the supercharger drive belt more heavily. The 60,000 km change interval must be strictly observed.
Symptoms: Squealing noises, power loss under load.
Direct-injection oil carbon on the unwashed intake valves. In the CTUA under sporty S6 conditions, reinforced by part-load EGR operation.
Symptoms: Hesitation, power loss, cold-start problems, rough idle.
Failed membrane in the oil separator leads to elevated oil consumption and fault codes. In sporty S6/A7 use the higher blowby pressure places greater stress on it.
Symptoms: Whistling noise, power loss, false air fault codes, elevated oil consumption.
Vehicle Weaknesses 9
On model years 2015–2018, the locking bolt of the tow bar can fracture, potentially causing the trailer to become detached while driving. Free workshop visit required.
The Multitronic CVT gearbox has a notoriously poor reliability record. Improved on the C7, it remains a risk. Total failure possible from 100,000 km; repair is very costly.
A material defect can cause the camshafts in the 3.0 TDI to fracture, leading to engine damage. Mainly affects vehicles from model year 2014 to early 2017.
The optional air suspension (AAS) is prone to failure through porous air bellows and defective compressors. Repair costs of 600–1,800 EUR per corner are possible.
LED headlights fail due to defective control modules or individual LEDs. Repair is often more expensive than replacement, as modules cannot be replaced individually.
The automatic climate control shows malfunctions from around 60,000 km: incorrect temperature regulation, blower stage issues or complete failure of individual zones on the three-zone system.
Wheel bearings, particularly at the rear axle, show increased wear at higher mileages. Regularly flagged on vehicles from 80,000 km.
On the C7, rust occurs primarily on the underbody and sills, sometimes in hard-to-reach areas. On vehicles over 7 years old, the underbody should be thoroughly inspected.
On V6 and V8 engines, engine mounts often wear from around 50,000 km, causing noticeable vibrations.