The 2015 S8 with the 4.0T twin-turbo V8 is a phenomenal performer when healthy, but the EA824 engine has serious internal weaknesses that can lead to catastrophic failures, plus the typical D4-platform transmission and fuel system issues that plague high-performance Audis of this era.
Catastrophic Engine Failure - Piston Ring Land & Cylinder Scoring
Common · high severity
Typical onset: 60,000-100,000 mi
Symptoms: excessive oil consumption (1qt per 1000mi or worse), blue smoke on cold start or acceleration, misfires and rough idle, metallic knocking from engine block, check engine light with cylinder misfire codes
Fix: The EA824 4.0T suffers piston ring land failures where the top ring groove cracks, allowing blow-by that scores cylinders. Once scoring begins, it's a complete engine rebuild or long-block replacement. Rebuild includes new pistons, rings, honing or sleeving cylinders, plus all gaskets and seals. Expect 40-60 labor hours for full tear-down and rebuild, or 25-35 hours for long-block swap if you can source one.
Estimated cost: $18,000-28,000
Turbocharger Failure (Hot-Side Components)
Occasional · high severity
Typical onset: 80,000-120,000 mi
Symptoms: loss of boost pressure, excessive exhaust smoke, loud whistling or grinding from engine bay, oil leaking from turbo seals, limp mode activation
Fix: Hot-side turbine wheels crack or exhaust side bearings fail, especially if oil changes were stretched. Replacement requires removing the entire engine in this chassis for proper access—Audi's design puts turbos in the valley between cylinder banks. You're looking at 18-24 hours labor for one turbo, 28-35 hours if both need replacement. Parts are $2,500-3,500 per turbo plus miscellaneous gaskets and fluids.
Estimated cost: $6,500-9,500
Transmission Oil Cooler Leak & Thermostat Failure
Common · medium severity
Typical onset: 70,000-110,000 mi
Symptoms: transmission fluid dripping under vehicle, delayed or harsh shifting when cold, transmission temperature warning, pink or red fluid visible at radiator area
Fix: The ZF 8HP transmission cooler develops leaks at fittings or the internal thermostat fails closed, causing overheating. Replacement requires dropping undertray, draining system, and replacing cooler assembly with updated o-rings. Count on 4-6 hours labor plus full fluid refill (9qts of ZF Lifeguard 8). If caught early, trans itself is usually fine.
Estimated cost: $1,200-2,000
High-Pressure Fuel Line Leaks (Recall-Related)
Occasional · high severity
Symptoms: strong fuel smell in cabin or around engine bay, fuel pooling on intake manifold, hard starting or rough running, fuel pressure fault codes, visible fuel weeping at injector rail connections
Fix: NHTSA recalls covered some fuel delivery line failures, but many S8s still develop cracks in high-pressure lines running to direct injectors, especially where lines pass over hot turbo components. Lines must be replaced—cannot be repaired. Labor is 3-5 hours due to access issues around intake manifold and turbos. Fire risk makes this urgent when identified.
Estimated cost: $800-1,500
Transmission Mounts (All Three) Collapse
Common · medium severity
Typical onset: 60,000-90,000 mi
Symptoms: heavy clunk on 1-2 or 2-1 shifts, vibration at idle in Drive, driveline shudder during acceleration, visible sag or tearing in rubber mount sections
Fix: The S8's 605lb-ft torque destroys transmission mounts faster than lower-output A8s. All three mounts (front, rear, cross-member) typically need replacement together. Requires lifting trans slightly for access to each mount point. 5-7 hours labor total for all three plus alignment check afterward.
Estimated cost: $1,400-2,200
Carbon Buildup on Intake Valves
Common · low severity
Typical onset: 50,000-80,000 mi
Symptoms: rough idle when cold, hesitation or stumble during light acceleration, reduced fuel economy, occasional misfire codes that clear
Fix: Direct-injection engines with no port injection get heavy carbon deposits. Walnut blasting is the proper fix—requires removing intake manifold and blasting each port with crushed walnut shells. 6-8 hours labor depending on how buried everything is under the intake and charge piping.
Estimated cost: $800-1,400
Owner tips
Change oil every 5,000 miles maximum with Audi-approved 5W-40 synthetic—extended intervals accelerate piston ring land failures
Monitor oil consumption religiously from day one; more than 1qt per 3,000mi means rings are already failing
Use only premium 93-octane fuel and keep fuel system clean—carbon buildup and low octane increase knock risk on already-fragile pistons
Budget $2,000-3,000 annually for repairs after 70k miles; these are not cheap to maintain even if you avoid the catastrophic engine issues
Only buy if you have a $20k emergency fund for engine replacement and accept that it's a question of 'when' not 'if' with the EA824 V8—spectacular car, but financially ruinous for most used buyers.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.
Fitment notes: AGM battery required for start-stop system; located under rear seat
As an Amazon Associate, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.
Every control module on the 2013-2017 Audi S8 — where it lives, replacement time, and what it takes to program a replacement. Modules marked dealer / factory tool won't work after a part swap alone — budget for programming.
⚠️ Two modules; memory positions lost on replacement. Massage/ventilation functions included.
Rear View Camera Control Module (RVC)0.5 hr R&Raftermarket tool +0.2 hr▸ programming details
📍 Trunk lid, integrated with camera
🔧 VCDS or Autel
⚠️ Calibration lines may need adjustment.
Aftermarket tool coverage varies by software version and vehicle build — treat "aftermarket tool" rows as "usually possible" and verify against your tool maker's coverage list before promising a customer. Spot a wrong location or hour? Tell us — corrections ship fast here.
ENGINE AND ENGINE COOLING:ENGINE:GASOLINE:TURBO/SUPERCHARGER · 22V178000
2022-03-23 · PE21009
Volkswagen Group of America, Inc. (Audi) is recalling certain 2013-2017 A8, S6 Sedan, S7, S8, and 2014-2017 RS7 vehicles. The turbocharger oil supply strainer can become blocked, causing wear to the bearings due to lack of lubrication.
Consequence: Worn bearings can cause the turbine wheel to contact the turbocharger housing or cause the shaft to break, causing an engine stall and increasing the risk of a crash.
Remedy: Dealers will replace the oil strainer and perform an oil change, free of charge. Owner notification letters were mailed August 4, 2022. Owners may contact Audi customer service at 1-800-253-2834. Audi's number for this recall is 21H7.
STRUCTURE:BODY:HOOD · 20V397000
2020-07-07
Volkswagen Group of America, Inc. (Volkswagen) is recalling certain 2013-2018 Audi S8 and A8 vehicles. The seal around the engine compartment may come loose and contact hot engine components.
Consequence: If the seal contacts hot engine components, there could be an increased risk of a fire.
Remedy: Audi will notify owners, and dealers will install a retaining plate to prevent the engine compartment seal from loosening. The recall began September 4, 2020. Owners may contact Audi customer service at 1-800-253-2834. Volkswagen's number for this recall is 51G6.
FUEL SYSTEM, GASOLINE:DELIVERY:HOSES, LINES/PIPING, AND FITTINGS · 19V057000
2019-01-28
Volkswagen Group of America, Inc. (Volkswagen) is recalling certain 2013-2016 Audi A8 and S8 vehicles. The fuel supply line for the high pressure fuel pump may become porous and leak fuel.
Consequence: Leaking fuel, in the presence of an ignition source, increases the risk of fire.
Remedy: Audi has notified owners, and dealers will install a fuel pressure damper, free of charge. The recall began February 21, 2019. Owners may contact Audi customer service at 1-800-253-2834. Volkswagen's number for this recall is 20BM.
FUEL SYSTEM, GASOLINE:DELIVERY:HOSES, LINES/PIPING, AND FITTINGS · 18V430000
2018-06-25
Volkswagen Group of America, Inc. (Volkswagen) is recalling certain 2013-2015 Audi S8 and A8 vehicles. The fuel supply line for the high pressure fuel pump may become porous over time, resulting in a fuel leak.
Consequence: A fuel leak in the presence of an ignition source can increase the risk of a fire.
Remedy: Audi will notify owners, and dealers will replace the fuel line, free of charge. The recall began July 20, 2018. Owners may contact Audi customer service at 1-800-253-2834. Volkswagen's number for this recall is 20AV.
Performance
Horsepower
605hp
Torque
516lb-ft
0–60 mph
3.5sec
Quarter mile
11.8sec
Top speed
155mph
Fuel economy (EPA)
City
16mpg
Highway
27mpg
Combined
20mpg
Fuel
Premium Gasoline
Capability & size
Curb weight
4,685lb
EPA class
Midsize Cars
Wiper blades
D4 generation (2013-2018). Sedan body style has no rear wiper.
Size-standard part numbers — verify your connector type before buying. Rear blades are model-specific; check the package's vehicle list.
Fuel economy figures are EPA data via fueleconomy.gov (median across matching trims). Performance figures are compiled estimates for the 2015 Audi S8 4.0L Turbo V8 and can vary by trim.
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Lexus & Toyota Mechanic · 20+ years.