Buying a Used Audi A6 and S6 C7: Complete Reliability Guide and Which Models to Avoid
The Audi A6 C7 (2012–2018) combines German luxury with a sharp, understated design and a wide choice of powerful engines. Whether you’re considering the efficient 2.0 TFSI, the torquey 3.0 TDI, or the mighty twin-turbo S6, this generation of the A6 offers refinement, technology, and comfort that still feel modern today.
However, beneath its elegant exterior, some engines and model years are more reliable than others. This guide explores the real-world reliability of the Audi A6 and S6 C7 in the U.S. market — highlighting common issues, maintenance costs, and which models to approach with caution.
Overview: How Reliable Is the Audi A6 C7?
The C7-generation A6 is generally more reliable than the outgoing C6, thanks to improved engines, refined electronics, and the introduction of Audi’s new MLB platform. Still, it’s a complex luxury car — with advanced electronics, air suspension (on some models), and turbocharged engines — so maintenance costs can add up.
With proper servicing and fluid changes, the C7 A6 can easily reach 150,000+ miles. The key is choosing the right engine and avoiding cars with deferred maintenance or oil consumption problems.
Common Problems Across All C7 A6 and S6 Models
-
Oil consumption: Common on early TFSI engines due to piston ring design.
-
Coolant leaks: From thermostat housing and water pump (especially on 3.0T engines).
-
PCV valve failures: Leading to rough idle and excessive oil use.
-
Timing chain rattle: Possible on high-mileage 3.0T and 4.0T engines, especially at cold start.
-
Electronics gremlins: Infotainment freezes, MMI screen failures, and door lock actuator faults.
-
Suspension wear: Control arm bushings and adaptive dampers wear out sooner on heavy or sporty models.
-
Carbon buildup: Common on all direct-injection petrol engines after ~60k miles.
Engine-by-Engine Reliability Breakdown
Audi A6 2.0 TFSI (EA888 Gen 2 and Gen 3)
Used in early 2012–2015 A6 models, the 2.0 TFSI is efficient and smooth but known for oil consumption and timing chain issues in earlier builds.
Common issues:
-
Excessive oil consumption due to worn piston rings.
-
PCV valve and rear main seal leaks.
-
Timing chain tensioner wear (risk of chain jump).
-
Carbon buildup affecting idle and performance.
Verdict:
Avoid early 2012–2014 cars unless they’ve had the updated piston rings or short block replaced under warranty. Later Gen 3 (2015+) versions are far more reliable.
Audi A6 3.0 TFSI (Supercharged V6, EA837)
The 3.0T is the best all-around engine for the C7 — offering strong performance and impressive reliability when maintained. Found in the A6 3.0T, A7, and S4, this supercharged unit is shared across many Audi models.
Common issues:
-
Water pump and thermostat leaks (plastic housings crack with age).
-
Carbon buildup on intake valves.
-
PCV valve failure causing vacuum leaks.
-
Cooling system hose and intercooler pump failures on high-mileage cars.
Verdict:
One of Audi’s most reliable modern engines. Regular coolant and oil changes keep it running strong. Highly recommended for performance and reliability balance.
Audi A6 3.0 TDI (Diesel)
Offered in select U.S. models, the 3.0 TDI is smooth, powerful, and efficient — but has its own maintenance quirks.
Common issues:
-
EGR valve clogging and DPF (diesel particulate filter) issues.
-
Intake swirl flap motor failures.
-
Oil cooler leaks and turbo actuator issues.
Verdict:
Excellent long-distance cruiser and reliable if driven regularly. Avoid cars used for short trips or city driving. Diesel emissions system repairs can be expensive.
Audi S6 (4.0 TFSI Twin-Turbo V8, EA824)
The S6 C7 uses the potent 4.0L twin-turbo V8, delivering 420–450 hp and serious performance. It’s a masterpiece of engineering — but also complex and expensive to maintain.
Common issues:
-
Oil consumption: Early engines burn oil due to valve seal wear.
-
Turbocharger failure: Turbos sit in the “hot V” — heat buildup can cause oil coking and bearing wear.
-
Timing chain rattle: Typically on cold start after 70k–90k miles.
-
PCV and crankcase breather failures.
-
Carbon buildup: Common in all S6 engines, especially those driven short distances.
Verdict:
When maintained, the 4.0T is durable and thrilling. Oil changes every 5,000 miles and turbo cooling upgrades (where possible) are essential. Avoid neglected or tuned cars without supporting modifications.
Transmission and Drivetrain Reliability
-
DL501 7-Speed S-Tronic (Dual-Clutch): Found in S6 and some A6 3.0T models. Robust but requires fluid changes every 35–40k miles. Mechatronic failures are rare but expensive.
-
ZF 8-Speed Automatic (Tiptronic): Used in most A6 2.0T and 3.0T models — smooth and reliable, but fluid should be replaced every 60k miles.
-
Quattro AWD: Strong and dependable; differential and transfer case fluid changes are often overlooked but crucial for longevity.
Which Audi A6/S6 C7 Models to Avoid
-
Early 2.0 TFSI (2012–2014) models with oil consumption issues.
-
Neglected 4.0T S6 cars with no turbo or PCV service history.
-
Tuned or modified S6s without upgraded cooling or regular oil changes.
-
Diesel TDIs used mainly for short city trips.
Buying a well-documented, unmodified example will save thousands in repairs later.
Upgrade and Customize Your Audi A6 or S6 C7
Enhance your Audi’s presence and performance with our premium selection of accessories made for the A6 and S6 C7. Add a sporty touch with black Audi emblems, RS-style honeycomb grilles, carbon fiber mirror caps, and front lips for an aggressive look.
Upgrade your tech with CarPlay retrofit modules, or refine your cabin with carbon interior trims and aluminum paddle shifters.
Complete your setup with rear diffusers and spoilers for that RS-inspired finish. All products include free shipping and a 1-year warranty, combining elegance, quality, and precision for your Audi.
What to Check Before Buying a Used Audi A6 or S6 C7
-
Verify full service history — especially oil, coolant, and transmission fluid changes.
-
Check for oil leaks near the front timing cover and valve covers.
-
Listen for timing chain rattle on cold start.
-
Scan for engine codes (PCV, misfire, or boost pressure faults).
-
Inspect MMI screen, backup camera, and all electronics.
-
Ensure Quattro system and transmission shift smoothly.
-
On S6 models, inspect turbos for whine or smoke.
Verdict: Is the Audi A6/S6 C7 Reliable?
The Audi A6 C7 is one of the most refined and dependable luxury sedans in its class — provided you choose the right engine and stay on top of maintenance.
-
The 3.0T (supercharged V6) is the sweet spot for reliability and performance.
-
The 2.0T can be solid after 2015, but early versions suffer from oil use.
-
The S6 4.0T is a thrilling powerhouse, but ownership costs are higher — buy only with full records.
Properly maintained, the A6 C7 offers a superb mix of comfort, technology, and performance that still rivals newer sedans today.