What goes wrong, what it costs, and what to check before you buy a used Audi RS6.
The Audi RS6 occupies a niche position on the UK market.
We track 5 known issues across the Audi RS6 range, with 4 classified as significant. Knowing which variants and configurations to approach with caution can save you from expensive surprises after purchase.
Found a Audi RS6? Enter the reg to see which of our 5 known issues apply to that exact car, plus full MOT history and mileage checks.
C5 (1999–2005) — Engine options included the 4.2 V8. We track 1 known issues on this generation, with 1 classified as significant. The most significant concern is Timing chain tensioner wear (£1,500–£3,000 to address).
C6 (2008–2010) — Engine options included the 5.0 V10. We track 1 known issues on this generation, with 1 classified as significant. The most significant concern is Shock absorber failure (£600–£1,200 to address).
C7 (2013–2018) — Engine options included the 4.0 V8 Biturbo. We track 3 known issues on this generation, with 2 classified as significant. The most significant concern is Turbo coolant line failure (£400–£800 to address).
The flexible coolant lines that supply the turbochargers on the 4.0 V8 biturbo engine are prone to failure at the connection points to the turbocharger housings. These lines carry pressurised coolant at high temperatures and the rubber-to-metal joints deteriorate over time, causing external coolant leaks. This is a known weakness specific to the C7 RS6 and RS7 models with early production dates. Failure typically occurs between 30,000-80,000 miles and requires immediate attention to prevent turbocharger overheating.
Coolant loss leads to turbocharger overheating and potential catastrophic turbo failure. A failed turbocharger can cost £3,000-£5,000 to replace. The engine may overheat if coolant loss is severe, risking head gasket failure and complete engine rebuild requirements.
Check the coolant level and look for any white residue or staining around hoses, the expansion tank and radiator. After a test drive, check the temperature gauge stayed stable and look underneath for drips. Ask whether key cooling components have been replaced.
The 4.0 V8 biturbo engine uses direct injection without port injection, causing carbon deposits to build up on intake valves over time. This affects all FSI and TFSI Audi engines but is particularly problematic on high-performance variants like the RS6 due to the aggressive tuning and boost levels. Carbon buildup restricts airflow into the cylinders, causing rough idle, misfires, and reduced power output. The only effective remedy is walnut shell blasting to physically remove the deposits from the valve surfaces.
Progressive power loss and poor fuel economy. Severe carbon buildup can cause intake valve damage and misfires that damage catalytic converters. Walnut blasting costs £500-£1,500 and should be performed every 40,000-60,000 miles as preventive maintenance.
Check for rough idle, hesitation or misfires during the test drive. Listen for the fuel pump priming when you turn the ignition on. Carbon buildup issues are more common on direct-injection engines — ask about intake cleaning history.
The C6 RS6 with 5.0 V10 engine shows elevated shock absorber failure rates at 80,000-100,000 miles, failing MOT tests at 2.7 times the national fleet average. The additional weight of the V10 engine and the aggressive suspension tuning places higher loads on the damper components compared to standard A6 models. Failed dampers compromise handling and braking performance on this high-performance variant.
Failed dampers compromise vehicle stability, increase braking distances, and cause premature tyre wear. On a high-performance car like the RS6, this significantly affects safety and driving dynamics. Replacement costs £800-£2,000 depending on whether OEM or aftermarket units are fitted.
Listen for knocking, clunking or rattling over bumps during the test drive. Inspect the underside for corroded or cracked suspension components. Check the MOT history for suspension-related advisories, which often predict future failures.
The 4.2 V8 engine in the C5 RS6 uses timing chains with hydraulic tensioners that can lose pressure over time, allowing chain slack to develop. This is a widely documented issue across Audi's V8 engines of this era. Chain stretch and tensioner wear cause timing variations that affect performance and can lead to valve contact with pistons if the chain jumps timing. The issue typically manifests between 80,000-140,000 miles.
Progressive timing chain stretch reduces engine performance and fuel economy. Complete failure can cause valve-to-piston contact, requiring a complete engine rebuild costing £8,000-£15,000. Timing chain replacement costs £2,000-£4,000 but prevents catastrophic engine damage.
Listen carefully for a rattle or ticking noise from the engine on cold start — this is the most common early sign. Ask for evidence of chain replacement in the service history. On higher-mileage cars without documented replacement, budget for preventative work.
The C7 RS6 with 4.0 V8 biturbo engine shows elevated suspension bush and joint wear at 40,000-60,000 miles, failing MOT tests at 2.6 times the national fleet average. The additional performance and weight of this variant, combined with stiffer suspension settings, accelerates wear of rubber bushes and ball joints compared to standard A6 models. This affects ride quality and handling precision.
Worn suspension bushes cause knocking noises, reduced handling precision, and uneven tyre wear. While not immediately dangerous, the degraded handling characteristics are particularly noticeable on a performance car. Replacement involves multiple components and typically costs £300-£800 depending on which bushes require renewal.
Listen for knocking, clunking or rattling over bumps during the test drive. Inspect the underside for corroded or cracked suspension components. Check the MOT history for suspension-related advisories, which often predict future failures.
For the full breakdown of all 5 tracked issues with repair costs, see the Audi RS6 common problems page.
Based on 4k real DVSA MOT tests, the Audi RS6 fails more often than average on several items. The biggest outlier is tyre tread depth not in accordance with the req... at 5x the fleet average.
Routine servicing (oil and filter change every 10k miles) typically costs £120–£180 at an independent garage.
The bigger-ticket items to budget for include spark plugs (£200–£350), automatic transmission fluid (£300–£500).
See the full Audi RS6 service schedule for every interval and cost breakdown.
The Audi RS6 is a solid choice on the used market, though not without its quirks. The issues we track are well-understood and largely avoidable if you know what to look for. A thorough inspection and complete service history go a long way.
Before committing, check the car's full MOT history, verify the service record is complete, and if possible arrange a specialist inspection. Enter any registration into our free report to see the complete picture.
Get Car Wise maintains a database of known mechanical issues for every popular car on UK roads, tracking the faults that owners, specialists and DVSA data reveal.
When you run a report on a specific Audi RS6, we cross-reference the exact variant, engine and age against our database of 5 known issues. Combined with full MOT history analysis, mileage verification and DVLA data, you get a complete picture before viewing.
Enter the registration for MOT history, mileage verification, known faults for that exact variant, and a Get Car Wise Score.
This guide was compiled from independent expert reviews, DVSA MOT data, specialist workshops and our own database of 5 known Audi RS6 issues. We are not affiliated with any source listed.