Audi A6
Supercharged V6 with 228 kW. Powerful and rev-happy engine, but the supercharger drive belt is a known wear item.
310 horses in a business suit
The CGWB turns the A6 C7 into a proper sleeper: outwardly a distinguished business traveller, under the bonnet a V6 that pushes effortlessly from low revs without ever needing to be asked.
Engine Weaknesses 8
The integrated intercooler in the Eaton supercharger fails due to thermal fatigue. Coolant enters the cylinders via the intake — risk of hydraulic lock engine damage.
Symptoms: Coolant loss without external leaks, cylinder 3 misfires, white exhaust cloud, power loss.
As across the EA837 family, the upper chain tensioners in the CGWB lose oil pressure at rest. Brief cold-start rattle. CGWB-specific: missing check valves in the oil passage accelerate pressure loss.
Symptoms: Metallic rattle 1–2 seconds after engine start, fades as oil pressure rises. Persistent noise with damaged chain guides.
Coolant pump and thermostat fail at high mileages. A6 C7 with 3.0 TFSI also has engine mount problems around 50,000 km that increase thermal stress.
Symptoms: Temperature gauge fluctuates or rises too high, coolant loss, cold engine on start despite warm-up.
Manufacturing tolerances on the high-pressure fuel lines cause leaks that allow fuel vapour to enter the cabin. Known problem on A6/A7 C7 3.0 TFSI.
Symptoms: Fuel smell inside after switching off, especially when engine is warm.
The front Eaton supercharger bearing wears at high mileages. The whistling noise is often mistaken for gearbox noise. In the extreme case supercharger seizure is possible.
Symptoms: High-frequency whistling or whining from the supercharger area, rev-dependent, no power loss in early stage.
Audi internally reduced the change interval from 90,000 to 60,000 km. Owners with older service books change too late. Belt failure causes immediate boost loss and can damage the supercharger.
Symptoms: Squealing from the belt area, sudden power loss, in the worst case a loud bang on belt failure.
As a direct-injection engine, the CGWB does not wash intake valves with fuel. Crankcase oil mist settles on the valves and carbonises. Recommended: walnut blasting from 80,000 km.
Symptoms: Hesitation at part throttle, power loss, poor cold starts, rough idle.
The membrane in the oil separator of the crankcase ventilation can tear and draw oil vapour uncontrolled into the intake. Leads to elevated oil consumption and coke build-up in the intake.
Symptoms: Power loss, rough running, false air fault codes, elevated oil consumption, whistling from engine bay.
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.