Audi A8
Supercharged V6 with 245 kW. More powerful variant of the 3.0 TFSI in the A8 D4 after model update. Effortless power delivery.
333 hp give the flagship its dignity
With the most powerful supercharged V6, the A8 D4 actually makes sense as a V6 choice: the performance is tangible and the supercharger suits the cabin's silent elegance better than a booming V8.
Engine Weaknesses 7
Thermal fatigue of the internal intercooler in the Eaton supercharger can allow coolant into the combustion chamber — risk of hydraulic lock engine damage.
Symptoms: Coolant loss without visible external leakage, misfires, white exhaust cloud.
The CGXB (North America variant of the CGWB, 245 kW) shares the same chain tensioner weakness. Oil pressure drops at rest, brief rattle on cold start. Missing check valves in the oil passage compound the problem.
Symptoms: 1–2 seconds of chain rattle after cold start, progressive: permanent rattle.
The coolant pump fails at high mileages. In the heavy A8 body with air suspension, the cooling system is more heavily stressed, promoting failures.
Symptoms: Overheating warning, coolant loss, engine running hot.
At high mileages the front Eaton supercharger bearing wears. Due to the higher boost in the CGXB (245 kW vs 213 kW CGWA), the bearing is under greater stress.
Symptoms: Whistling, rev-proportional noise from the supercharger direction.
The Eaton supercharger drive belt must be replaced every 60,000 km. The CGXB runs at higher boost than the CGWB, placing greater load on the belt.
Symptoms: Squealing from belt area, power loss under load, immediate boost loss on failure.
As a direct-injection engine, the CGXB forms oil carbon deposits on intake valves. Walnut blasting every 60,000–80,000 km recommended.
Symptoms: Hesitation, power loss, poor cold-start behaviour, rough idle.
Alusil cylinder bore wear or faulty crankcase ventilation leads to elevated oil consumption. In the A8 with long service intervals this is often noticed late.
Symptoms: Oil consumption above 0.5 L/1,000 km, bluish exhaust, oil smell.
Vehicle Weaknesses 13
The adaptive air suspension on the A8 D4 is a well-known money pit. Air bellows become porous, the compressor runs non-stop and overheats. Repairing all four corners costs several thousand euros.
The 4.2 TDI V8 in the A8 D4 has a timing chain that is prone to premature wear when neglected. A break causes severe engine damage. Replacement requires complete engine removal.
The 4.2 FSI V8 has four timing chains with phenolic resin guide rails that become brittle with age. Neglected oil changes risk chain skip.
Turbocharger bearings can wear and bring the turbine wheel into contact with the housing. Audi recalled around 26,000 vehicles in 2022.
Leaking air bellows cause the vehicle to sink and force the compressor into continuous operation until it fails. Front and rear are equally likely to be affected.
The MMI multimedia system stands out from 60,000–100,000 km with frozen screens and unresponsive controls. Multiple control modules can be affected.
The ZF 8-speed automatic shows harsh gear changes and gear selection problems at high mileage. Regular oil changes (every 80,000 km) are critical.
The MMI multimedia system is known for total failures caused by overvoltage damage after battery replacement or moisture damage to the Bluetooth control module.
The rubber-metal bushes of the front control arms on the heavy A8 D3 show significant wear at high mileage.
Front and rear control arm rubber bushes go soft with increasing mileage. The A8's considerable weight accelerates wear.
The 6-speed Tiptronic shows harsh gear changes at high mileage. A gearbox oil change often resolves the problem.
With increasing age the driver's side window regulator switch block on the A8 D3 frequently fails. The switch block must be completely removed for replacement. Pixel failures in the instrument cluster and screen faults are further typical age-related symptoms.
Almost all A8 D3s show worn and peeling soft-touch surfaces on light switches, trim panels and control knobs. The coating detaches in strips, leaving a sticky surface that is visually badly affected.
Reports & Tests
124 owner complaints filed with NHTSA (2010–2017). Most reported: Engine (78), Other (13), Fuel System (12).