Audi A8
6.3-litre W12 with 500 PS — two VR6 blocks in V-configuration. Mechanically reliable with correct care; typical weaknesses are ignition coils, injectors and cooling system leaks. Shorter oil change intervals (max. 10,000 km) strongly recommended. Specialist workshop required for servicing — standard workshop equipment is not sufficient.
Sporting character — driving fun guaranteed
500 hp 6.3L with noticeable temperament.
Engine Weaknesses 5
The W12 has four catalytic converters and eight lambda sensors. With increasing mileage, sensors and cats fail. In the worst case the engine must be removed to access the rear catalytic converters.
Symptoms: Engine warning light, fault codes for lambda sensor control (bank 1/2 lean/rich), elevated fuel consumption, power loss.
The W12 cooling system is exceptionally complex and prone to leaks. Under high load or with faults, overheating is a risk. Coolant pumps, thermostats and expansion tanks must be checked regularly.
Symptoms: Coolant temperature rises unusually quickly, coolant loss without visible leakage, heater gives little heat.
The W12 has 12 ignition coils that fail individually or in groups with increasing age. Due to the engine architecture, replacing the rear coils is very labour-intensive.
Symptoms: Misfires, rough running especially at idle and under load, engine warning light with misfire fault code for individual cylinders.
The A8 range with W12 suffers from numerous electrical problems. Particularly early build years (to mid-2004) had serious MMI system problems and poorly calibrated air suspension.
Symptoms: MMI system fault messages, failure of individual comfort functions, erratic air suspension, sporadic warning lights without apparent cause.
The W12 holds approximately 10.5 litres of engine oil. Even moderate consumption of 0.5 L/10,000 km adds up to high operating costs. Shorter oil change intervals (10,000 instead of 15,000 km) are recommended.
Symptoms: Regelmäßig sinkender Ölstand zwischen den Wartungsintervallen, Wartungskosten deutlich über Normalfahrzeugen.
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).