Audi RS Q8
The third-generation EA825: technically identical at its core to the Lamborghini Urus and Porsche Cayenne Turbo. 600 PS, cylinder deactivation (4 of 8 at part load), 48V mild hybrid with belt starter-generator, rear-wheel steering. This makes the RS6 C8 surprisingly agile despite weighing over 2.1 tonnes. C7 owners report slightly duller throttle response in stock form — ECU/TCU mapping is often updated. Alternator fails unexpectedly early under high-performance use: 30,000–50,000 km lifespan documented on some examples. Engine itself has no characteristic weaknesses under normal use.
RS Q8 — 600 hp SUV, more liveable than the Urus
Same platform as the Lamborghini Urus, €100k cheaper. 600 hp moves 2.3 tons to 60 mph in 3.8 seconds. More comfortable than the Urus daily, slower on track. For the audience that wants Urus performance without Lamborghini attention.
Engine Weaknesses 10
Excessively fine-mesh oil strainer in the turbo oil supply clogs with carbon deposits. Result: turbo bearing starvation, turbo damage up to engine failure. Recall 21H7 (April 2022) affects production June 2012–March 2017.
Symptoms: Power loss, misfires, turbo whistling, oil burning
From around 150,000–200,000 km, timing chains can stretch or guide rails break. Camshaft-to-crankshaft synchronisation fault codes appear. Without repair, severe engine damage follows.
Symptoms: Rattling noise on cold start, rough idle, engine check light, camshaft fault codes
Hot-V mounted turbos tend to oil carbon buildup in drain lines when frequently shut down after full-load without cooldown time. Coking leads to turbo oil loss and bearing damage without immediate symptoms.
Symptoms: Blue smoke after parking, turbo bearing whine at high rpm, slowly increasing oil consumption, eventually power loss
Defective crankcase ventilation allows engine oil to enter the combustion chambers via the intake manifolds. Leads to uncontrolled combustion events, increased oil consumption and misfires.
Symptoms: Increased oil consumption, blue smoke from exhaust, misfires, rough running
In 4-cylinder mode (CoD system), some vehicles experience misfires (P0301 etc.) and stumbling when switching. Spark plugs can foul up in partial operation.
Symptoms: Stumbling during 4→8 cylinder transition, misfire fault codes, MIL lamp
The 48V mild hybrid RSG (part number 4N0→4N1 after revision) is known problematic on the RS6 C8, RSQ8 and related models. Multiple failures in short periods documented; KBA recall 2020 for moisture ingress.
Symptoms: Electrical system warning, vehicle shuts itself down, 48V warning indicator, start-stop failure, in worst case complete voltage failure
The C8 4.0 TFSI high-pressure pump can produce pressure drops under high mileage and extended full-throttle phases. Fuel quality and service intervals strongly influence service life.
Symptoms: Engine stumbling on cold start, power loss at full throttle, low fuel pressure fault code, starting difficulties at low temperatures
The ZF8HP gearbox is considered 'maintenance-free', tempting owners to skip fluid changes. With spirited driving and 600+ Nm, a change every 60,000 km is recommended to prevent damage.
Symptoms: Slight shift jerk on pull-away and after gear changes, shift hesitation with sporty driving style, in advanced stage: gearbox limp mode
Engine mounts on the RS6 C7 show increased wear, often from as early as 50,000 km. Typical for heavy V8 units with high torque spread. Replacement is labour-intensive.
Symptoms: Vibrations inside the cabin, droning during load changes, perceptible roughness at standstill
The cylinder deactivation (CoD) on cylinders 2, 3, 5, 8 causes thermal cycling on the spark plugs of those cylinders. Recommended replacement interval of 40,000 km should be shortened for high-performance use.
Symptoms: Misfires on CoD cylinders after reactivation, stumbling on cold start, engine warning light with misfire fault code
Vehicle Weaknesses 6
Faulty sensors in both front doors can affect side airbags, head airbags and belt tensioners. RAPEX notification INFO/00089/21, April 2021. Free repair at authorised dealer.
High-voltage battery cell modules can overheat when charging and cause a vehicle fire. KBA action 93QQ affects Q8 PHEV (60 TFSI e) from production period 08/2019–07/2024. Software update as fix, approx. 60 minutes workshop visit.
Oil can leak from the automatic gearbox cooling lines. Gearbox oil on the road increases accident risk. NHTSA campaign 20V272000, 531 vehicles affected.
On Q8 models from 2019–2021 (action 42L1) an incorrectly torqued rear axle nut can alter wheel alignment and affect driving stability. Free repair at dealer.
The Q8 4M air suspension shows typical weaknesses on residual pressure hold valves (approx. 50 € part) and air bags. Warning light illuminates, vehicle drops on one axle, compressor runs continuously to the point of overheating.
The Q8 MMI system crashes or loses favourite settings. The adaptive cruise control (ACC) sporadically reports 'unavailable'. The parking assistance system and head-up display can also be affected by software faults.
Reports & Tests
172 owner complaints filed with NHTSA (2018–2024). Most reported: Electrical (66), Powertrain (48), Engine (43).