Audi A8
Audi A8 6.0 W12 with 450 PS (331 kW) in the A8 D3 and D4. Unique 12-cylinder in W-configuration. Very refined and quiet drivetrain. High fuel consumption (17–20L/100km). Servicing very expensive and requires specialist knowledge.
Smooth Multi-Cylinder — Relaxed Cruising
450 hp 6.0L with a pleasantly smooth character. Cruises effortlessly without sporting ambitions. Factor in the known weak points.
Engine Weaknesses 5
The W12 has a very complex cooling system. Leaks at hoses, the thermostat or expansion tank are common. The cramped engine bay makes every repair extremely labour-intensive.
Symptoms: Coolant loss, rising temperature gauge, overheating warning, coolant smell
With inadequate maintenance (wrong oil, intervals too long) the W12 can develop engine damage quickly. Con-rod bearings and pistons are particularly at risk from oil starvation. Engine damage documented from around 130,000 km.
Symptoms: Knocking and hammering from the engine, high oil consumption, oil pressure warning, smoke from the engine
The W12 has 12 ignition coils, with individual coils failing regularly. A failure causes misfires on individual cylinders. The repair is labour-intensive and expensive due to accessibility issues.
Symptoms: Rough running, shaking at idle, fuel smell from the exhaust, OBD misfire fault codes
The W12 has four catalytic converters and eight lambda sensors. Failure of individual components is accelerated by misfires (faulty ignition coils). Replacing all cats costs up to €8,000.
Symptoms: Check engine light, elevated emissions, rough engine running, power loss
The A8 D3/D4 W12 features extensive electronics (MMI, sat-nav, reversing camera, lighting control). Failures of individual control units and sensors are more common than mechanical problems.
Symptoms: Navigation system freezes, reversing camera shows no image, lighting faults, various warning lights
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).