The ultimate performance wagon and one of the most desirable Audis ever made. The 4.0 TFSI twin-turbo V8 is generally robust when maintained properly, but turbo oil screen failures are the critical concern - Audi issued a recall in 2022 for 2013-2017 models. Timing chain tensioners can fail between 80,000-120,000 km causing expensive engine damage. DRC (Dynamic Ride Control) suspension is problematic and expensive when it fails, which it often does. Carbon buildup on intake valves requires walnut blasting every 60,000-80,000 km. Avoid any tuned/mapped cars - warranty will be voided and reliability compromised. Budget €3,000-5,000 annually for maintenance plus a substantial repair reserve.
Oil strainer becomes clogged with deposits, starving turbos of oil · more· less
This is the most critical issue with the C7 RS6. A pre-filter deep under the turbos can become clogged with oil deposits, causing oil starvation and turbo failure. Symptoms include loss of power, high-pitched whining noise, or blue/black exhaust smoke. Audi issued Safety Recall 21H7 in 2022 covering 2013-2017 models to replace the oil strainer with a larger mesh version. The recall started after analysis in 2014-2017 revealed deposits could accumulate and clog the strainer over time. Many owners follow strict 5,000 km oil change intervals with periodic oil cleaner flushes to prevent this. Turbo replacement at dealer can reach €5,000 per turbo in labor and parts. Always verify recall completion before purchase.
Timing chain tensioner failure€2,000 - €4,000
Tensioner loses pressure causing chain rattle and potential skip · more· less
The timing chain tensioners have a release valve that weakens over time, allowing oil pressure to bleed off overnight. This causes distinctive cold start rattle, particularly if the car sits for 3+ days. Typically occurs between 80,000-120,000 km. If you hear rattling for more than a few seconds on cold start, the chain, guides, tensioners, and sprockets all need replacing. Audi revised the tensioners at least 7 times up until 2016, but even revised versions still fail. Ignoring this can lead to chain skip and catastrophic valve/piston contact requiring engine rebuild. Parts are relatively cheap but labor is 8-10 hours due to V8 packaging.
Hydraulic dampers leak fluid, control valves fail · more· less
DRC is a mechanical-hydraulic system that connects shock absorbers diagonally with central valves. When it works, it's excellent, but it's notorious for reliability issues. One owner reported DRC failure at just 24,000 km. Another experienced 4 new dampers and at least 2 sets of control valves in 40,000 km over 3 years. The unreliability rumors are accurate - DRC fails at much earlier stages and far more commonly than standard air suspension. Dealer replacement cost is extremely high; specialist refurbishment can save up to 50%. Some owners convert to aftermarket KW coilovers (around €1,800 installed) rather than repair DRC. Air suspension is reportedly easier and cheaper to fix when it eventually fails.
Carbon buildup on intake valves€800 - €1,200
Direct injection engines build carbon on valves, reducing power and efficiency · more· less
TFSI engines are notorious for carbon buildup that robs power and efficiency by reducing airflow to cylinders. This affects virtually all high-mileage examples. Symptoms include rough idle, misfires, and gradual power loss. Requires walnut shell blasting every 60,000-80,000 km. The 4.0L V8 costs €800-1,200 at independent specialists, potentially more at dealers (one quoted €2,400 for manual cleaning). The job takes approximately 4 hours. Fuel quality and PCV valve condition affect buildup rate. While the valves are accessible, many owners replace spark plugs, ignition coils, and PCV components simultaneously to maximize value from the labor cost.
ZF 8-speed transmission issues€1,000 - €7,000
Fluid leaks, harsh shifting, valve body malfunction · more· less
The ZF 8-speed is generally reliable but can develop issues in high-mileage or hard-driven cars. Common problems include fluid leaks, torque converter shuddering, harsh shifting (often from low/contaminated fluid or faulty solenoid), and valve body malfunction. Minor repairs like solenoid replacement or leak fixes cost €1,000-2,000. Full rebuild runs €7,000-8,800. ZF recommends fluid replacement at 60,000 miles or sooner under "severe conditions," despite Audi claiming "lifetime" fluid. Independent specialists quote around €700 for fluid and filter service. Refurbished gearbox from ZF agent is approximately €2,000 if you deliver it to their workshop. Early intervention with fluid changes prevents expensive failures.
Water pump and thermostat housing failure€1,500 - €3,500
Plastic housing leaks, water pump fails around 70,000-100,000 km · more· less
Coolant leaks from plastic thermostat and water pump housings are extremely common on VW/Audi engines. The job is expensive because the front end, radiator assembly, flywheel, alternator, and oil cooler must be removed to access the pump. One S7 owner (same 4.0T engine) paid approximately €3,000 at dealer with 10 hours labor. Independent shops charge €1,500-2,500. Wrong coolant type or missing/loose housing bolts accelerate failures. The entire cooling system should be inspected when replacing the pump. Replace thermostat simultaneously - it's included in most repair kits. TSB 2036167 addressed turbo coolant line seepage on 2013 models.
Excessive oil consumption€50 - €200/year
Engine burns oil between services, Audi says up to 1L per 1,200 km is "acceptable" · more· less
The 4.0 TFSI is known to consume significant oil. Audi considers 0.5L per 1,000 km (1 liter per 1,200 miles) "within tolerance." One owner reported needing oil top-ups every 1,000 miles, which Audi said was acceptable. However, experiences vary widely - one owner did 36,000 miles without topping up between 9,000 mile services. Consumption depends heavily on driving style, oil brand, and whether the engine is fully warmed before hard use. Using performance before oil is warmed increases consumption markedly. Excessive consumption can indicate turbocharger wear or piston ring issues. Carbon buildup and PCV valve problems contribute. Some owners report Liqui Moly oil burns less than other brands. The engine requires 502 spec oil.
Brake disc warping€2,000 - €2,500 per set
Heavy car with high performance causes rapid brake wear and warping · more· less
The RS6 is brutal on brakes due to its 2,070 kg weight and 560+ horsepower. Brake discs are prone to warping, causing steering wobble at motorway speeds and pedal vibration. Discs and pads need replacement around every 50,000 km depending on driving style. OEM wavy-edge RS-specific discs cost over €1,000 per pair; generic alternatives are cheaper. Complete brake service (discs and pads front and rear) runs approximately €2,000-2,500. Carbon ceramic brakes (optional from factory for €9,000 premium) can last 100,000+ km versus 25,000-30,000 km for steel, but replacement cost is €20,000-25,000. Aftermarket carbon ceramic options (CTE, Triton) available at 50% of OEM cost.
Sport differential malfunction warning€500 - €14,000
Usually oil sensor issue, rarely actual differential failure · more· less
According to Audi, sport differential malfunction warnings are very rarely caused by the differential itself - usually it's the oil level sensor or insufficient differential oil. However, if ignored, low oil can lead to expensive differential damage. Some warnings appear alongside electrical system malfunctions related to the alternator/starter generator rather than the diff. Actual differential replacement can cost up to €14,000, though dealers sometimes agree to fit used units. Diagnostic costs at Audi dealer run around €1,000 just to identify the cause. Rear differential oil should be changed at 40,000 mile major service. Rear differential leaks covered under TSB warranty for some model years.
21-inch wheel failure / tire wear€1,500 - €2,500
21-inch wheels prone to bending, tires last only 15,000-25,000 km · more· less
The 21-inch wheel option is prone to failure and bending. Buyers should be wary of any RS6 on 21s - the ride should be smooth at 60-80 mph. If not, it likely has bent wheels, which are expensive to replace. Even without damage, the large wheels provide a harsh ride. Tires are expensive: Michelin Pilot Sport 4S (the "undisputed best tire") in 275/35R20 costs approximately €450-570 per tire and lasts around 20,000 miles. Pirelli P-Zero (factory option) gets poor reviews and wears faster. A full set of premium tires costs €1,800-2,300, needed every 25,000-40,000 km depending on driving style. Uneven tire wear indicates suspension or alignment issues.
Ignition coil / spark plug issues€400 - €800
Coil packs and plugs can cause misfires, replace at 75,000 miles · more· less
Spark plugs should be replaced at 75,000 miles (120,000 km) per factory specification, though some owners do it earlier at 50,000-60,000 miles. Stock plug is NGK SILFER8C7ES (part 06K-905-601-M). At UK Audi dealers, plugs cost approximately €200 and labor €400 (1.5 hours per bank), though this can be negotiated. Independent shops charge less. The job is straightforward DIY taking about 1.5 hours first time. Use anti-seize on threads and dielectric grease on coil boot, torque to 30 Nm. Some owners upgrade to APR coils for increased output. Stock coils don't typically need replacement unless faulty. Per-coil replacement costs €175-250 at dealers.
Expensive to maintain, but rewarding when properly cared for
The C7 RS6 is considered one of the most reliable RS models, but "reliable for an RS" still means significant maintenance costs. The 4.0 TFSI engine is robust when serviced correctly with frequent oil changes (every 5,000-10,000 km), quality fuel, and proper warm-up procedures. The turbo oil screen recall is critical - verify completion. DRC suspension and timing chain tensioners are the weak points. Avoid tuned cars - they're fast enough stock and mapping voids warranty while increasing failure risk.
Pre-Purchase Inspection Checklist
General checks
Complete service history essential
Must show regular oil changes every 5,000-10,000 km. Oil change interval is officially 10,000 miles/year but many owners do 5,000 km. Major service at 40,000 miles includes spark plugs, filters, and rear differential oil.
Cold start test
Engine must be completely cold (sitting overnight). Listen carefully for timing chain rattle in first 30 seconds. Any persistent rattling indicates expensive chain/tensioner work needed.
Extended test drive (minimum 30 minutes)
Must include motorway speeds to check for steering wobble (warped brakes), suspension operation in both comfort and sport modes, and transmission behavior when fully warmed.
Tire condition and wear pattern
Premium tires (Michelin PS4S) are expensive. Check tread depth and look for uneven wear indicating suspension/alignment issues. Verify tire age from date codes - old tires are safety hazard.
Specific for this vehicle
Verify turbo oil strainer recall 21H7 completed
Contact Audi dealer with VIN. This recall covers 2013-2017 models and is absolutely critical. Without this fix, turbo failure is almost inevitable.
Check for turbo issues during test drive
Listen for high-pitched whining or whistling during acceleration. Check for blue or black exhaust smoke. Loss of power or "limp mode" indicates turbo problems. These repairs cost €2,000-5,000 per turbo.
Inspect DRC suspension for leaks and operation
Look under car for oil on dampers. Test both comfort and sport modes - changes should be immediate and noticeable. Any warning lights or sluggish response indicates expensive problems. DRC failure is common and costs €3,000-6,000.
21-inch wheel inspection (if equipped)
Drive at 60-80 mph - ride should be smooth. Vibration indicates bent wheels. Inspect wheels carefully for cracks or bends. Replacement wheels are expensive and bending is common on 21s.
Check service records for carbon cleaning
Should have walnut blasting performed every 60,000-80,000 km. If approaching this interval and not done, budget €800-1,200 immediately. Symptoms include rough idle, misfires, gradual power loss.
Transmission fluid change history
ZF says change at 60,000-90,000 miles despite Audi "lifetime" claim. Check for smooth shifts, no harsh engagement, no whining noises. Fluid service costs €700; rebuilds cost €7,000+.
Check for tuning/mapping evidence
Avoid any mapped car - Audi will find evidence and void warranty. Even returned to stock, mapping leaves traces. Ask directly if ever tuned. Check for aftermarket intake, exhaust, or ECU-related modifications.
Coolant system inspection
Check coolant level and condition (should be pink/red, not brown/milky). Look for leaks around thermostat housing and water pump. Coolant warning light indicates €1,500-3,500 repair.
Oil consumption test if possible
Check oil level at start and end of test drive. Some consumption is normal (up to 1L per 1,200 km per Audi), but excessive use indicates turbo or piston ring wear.
Brake pedal feel and steering wobble test
Brake hard from 100 km/h multiple times. Pedal should be firm with no vibration. Steering wobble at 100-130 km/h indicates warped discs (€2,000-2,500 repair). Test both steel and ceramic brakes if equipped.
Check for oil leaks around valve covers and turbo seals
Turbocharged engines are prone to oil leaks. Inspect engine bay carefully. Valve cover gaskets become brittle from heat and pressure. Small leaks worsen over time.
Verify facelift vs pre-facelift (2015+)
Facelift cars have Matrix LED lights, double-glazed windows, upgraded MMI, and improved interior. A higher-mileage facelift is often better value than lower-mileage pre-facelift.
TSB 2036392/1: Engine mounts software updateShaky at 500-1000 rpm
Contact Audi dealer with VIN to verify all recalls and TSBs completed. The turbo oil strainer recall (21H7) is absolutely critical - this affects 2013-2017 models and prevents catastrophic turbo failure. Owner notification occurred August 2022.
Warranty Status
Factory warranty (2-3 years)Expired on all C7 models
Extended warranty (UK pricing)€550-1,100/year depending on mileage
Third-party warranty options€2,100-4,400 for multi-year coverage
All C7 RS6 models (2013-2018) are now outside factory warranty. Audi extended warranty costs approximately €550-1,100 per year in UK/Europe depending on mileage allowance (typically 10,000-16,000 km/year) with €250 excess. Watch mileage declarations carefully. Extended warranty can be worthwhile given repair costs - DRC suspension replacement alone is €5,000. However, any evidence of tuning/mapping voids warranty coverage.
This report is for informational purposes only and does not constitute professional advice. Estimates may be inaccurate. Always have a qualified specialist inspect the vehicle before purchase. We accept no liability for decisions made based on this information.