Audi A8
EA839 turbo V6 with 250 kW and 48V mild hybrid. Successor to the supercharged V6, now with exhaust turbocharger. Very refined and powerful engine.
Quiet gliding with a sensible engine
In the A8 D5 the DLZA provides discreet, refined progress. The A8 buyer will notice, however, that the V6 is not a V8: that last measure of nobility the flagship status demands is missing.
Engine Weaknesses 7
The EA839 DLZA (A6 C8, A7 4K, A8 D5) shares the known water pump weakness. Vacuum-controlled pump failure allows coolant to migrate into the vacuum system. Critical: 4-bolt pump still original, 6-bolt = already replaced.
Symptoms: Coolant warning light, coolant loss, P0299, 'drivetrain fault', start-stop disabled.
Early EA839 variants with poor-quality rocker arm rollers (GP0) are also possible in the DLZA. Rollers can fall out and cause camshaft and piston damage.
Symptoms: Combustion misfire, knocking from cylinder head, engine fault light, rough running.
The DLZA is fitted with a 48V MHEV. The belt starter-generator (BSG) and the 48V lithium-ion battery can fail. Control units before 2021 without moisture protection are vulnerable.
Symptoms: '48V system fault', rough starting, no recuperation, start-stop disabled, limp mode.
EA839 DLZA as a direct-injection engine without intake valve washing: oil mist from crankcase ventilation settles as coke on the valves. On long-distance A6/A7/A8 use often noticeable from 80,000 km.
Symptoms: Hesitation, cold-start weakness, power loss at part throttle.
Beyond water pump failure, EA839 engines in the business class (A6, A7, A8) also show coolant losses from seal failure. Regular coolant level checks important.
Symptoms: Coolant smell, dropping coolant level, overheating warning.
EA839 DLZA under high load shows elevated oil consumption from piston ring wear. With long service intervals in the A6/A7/A8 the problem can go unnoticed for some time.
Symptoms: Oil consumption above 0.5 L/1,000 km, bluish exhaust, oil smell.
In the extensively networked A6 C8 / A7 4K / A8 D5, occasional engine management sensor failures (boost pressure sensor, lambda) lead to the engine warning light without consequential damage.
Symptoms: Engine warning light, various fault codes, occasional power reduction.
Vehicle Weaknesses 6
A contact fault in the seat heating cable can cause the passenger occupant detection system (PODS) to detect a malfunction and deactivate the passenger airbag. Affects A8 model years 2017–2020. Free repair at dealer.
High-voltage battery cell modules can overheat during charging, in extreme cases causing a vehicle fire. KBA action 93QQ, production period 08/2019–07/2024. Solution: software update with improved temperature monitoring and charge current limiting.
The adaptive air suspension on the A8 D5 shows weaknesses from 100,000–150,000 km: rear air bellows become porous, the compressor overheats from continuous running when bellows leak. Cold temperatures worsen the sealing of the rubber membranes.
The 48-volt electrical system of the A8 D5 can produce charging faults on the lithium-ion buffer battery. When it fails, numerous warnings appear on the instrument cluster (assistance systems unavailable, steering, engine shutdown warning). Replacement is expensive.
The rubberised soft-touch surfaces on light switches, trim panels and door inner handles peel off on virtually all vehicles with age. A sticky, greasy surface develops especially on frequently touched areas.
The digital instrument cluster (Virtual Cockpit) occasionally freezes and the navigation map stops updating. 2021 models were recalled due to a hardware fault in the connection cable (software solution). Older models are mostly resolved through software updates.
Reports & Tests
7 owner complaints filed with NHTSA (2017–2024). Most reported: Electrical (3), Powertrain (3), Engine (2).