2004-2011 · 2.7L V6 TDI diesel (180 hp BPP engine)
Executive diesel with strong torque but complex maintenance profile. The 2.7 TDI shares most weaknesses with the 3.0 TDI: timing chain tensioner failures require engine removal (€2-5k), and the Multitronic CVT (if equipped) is fundamentally unreliable before 2008. Pre-2007 cars had problematic first-gen piezo injectors. DPF and EGR issues are common with short-trip driving. Avoid Multitronic, prioritize timing chain service history, and budget for diesel-specific maintenance.
Hydraulic tensioner loses pressure, chain rattles on cold start · more· less
The upper timing chain tensioner is hydraulic and wears over time, allowing the chain to slap around especially on cold starts. Listen for a rattle lasting 1-30 seconds after startup. If the chain jumps teeth, it causes timing issues and the ECU refuses to work. The repair requires significant disassembly - the upper tensioner can be done without pulling the engine (~€500-800 parts + labor), but if the lower tensioner also fails, engine removal is required. Total cost for full chain service: €2,500-5,000. Post-2007 cars got improved tensioners but the issue persists. Long oil change intervals accelerate wear.
Multitronic CVT gearbox failure€1,500 - €5,000
Pre-2008 CVT has fundamental reliability issues with high-torque diesels · more· less
If your A6 has the Multitronic CVT (not Tiptronic or manual), budget for problems. Pre-2008 cars have a 5-plate clutch that judders at low revs; Audi later upgraded to a 7-plate clutch (~€5,000 retrofit). The chain and cones wear (chain life ~180-250k km), and the control unit overheats. The TDI engines' high torque accelerates wear. The CVT cannot be towed for long distances. A new gearbox costs ~€5,000 fitted. Post-2008 models with 7-plate clutch are more reliable. Tiptronic or manual gearboxes are significantly more trouble-free.
Piezo injector failure€800 - €2,500
Pre-2007 first-gen piezo injectors fail prematurely · more· less
Early 2.7 TDI engines (pre-2006/2007) used first-generation piezo injectors known for premature failure. Symptoms include hard starting after sitting 10-20 minutes (fuel accumulates in combustion chamber), metallic knocking, rough running, and sudden power loss. Single injector replacement: €300-800. Full set of 6: €1,700-2,500. Injectors cannot be traditionally refurbished. Later production years got improved injectors. If buying, check for injector-related fault codes with VCDS.
DPF blockage€150 - €1,500
Short trips prevent regeneration, causing DPF clogging · more· less
The Diesel Particulate Filter clogs if the car is used mainly for short city trips - the exhaust never gets hot enough for regeneration. Warning light appears, power reduces. Forced regeneration at garage: €100-200. Professional DPF cleaning: €300-500. Full DPF replacement: €1,000-1,500. Regular highway driving (30+ minutes at higher RPM) helps prevent this. A stuck EGR valve accelerates DPF clogging.
EGR valve fouling€150 - €1,000
Carbon buildup causes EGR to stick, affecting performance · more· less
The EGR valve recirculates exhaust gases and becomes clogged with carbon over time, especially with short trips and low-quality diesel. When stuck open or closed, it causes rough idle, power loss, and accelerates DPF problems. Cleaning can restore function if not severely damaged: €100-200. Replacement: €500-1,000 (dealers quote €1,200-1,500). Independent specialists charge significantly less than Audi dealers.
Turbo actuator failure€150 - €1,500
Electronic actuator sticks from heat and carbon buildup · more· less
The turbo uses an electronic actuator (Hella unit on Garrett turbo) that can fail due to heat damage or carbon buildup. Symptoms: limp mode, reduced power, boost-related fault codes. Specialist actuator repair: €140-250. Full garage repair with recalibration: €250-500. VW/Audi dealers often replace the entire turbo (~€1,500) when only the actuator is faulty. Ask specifically about actuator-only repair.
Swirl flap / intake manifold€100 - €400
Linkage wears loose, triggers engine light and P2011/P2015 codes · more· less
The intake manifold swirl flaps are controlled by a motor with linkage that wears loose over time. The plastic guides wear through, triggering fault codes P2011 or P2015. Usually just the actuator rods need replacement - repair kits available for €30-50. Full manifold replacement: €365 + labor. Some owners delete the flaps and remap the ECU to ignore them.
Oil leaks (valve cover, cam seals)€300 - €800
Valve cover gaskets and camshaft seals harden with age · more· less
Common leak points: valve cover gaskets (oil drips onto exhaust, burning smell), camshaft seals (oil trail down front of engine), and cam chain tensioner gaskets at rear of cylinder head. Blocked crankcase ventilation increases internal pressure and accelerates leaks. Valve cover gasket replacement: €270-420. If doing cam seals, combine with timing belt/water pump service to save labor.
MMI system failure€300 - €1,500
Infotainment freezes, reboots, or fails completely · more· less
The MMI system (Multi Media Interface) can freeze, randomly reboot, or fail entirely. Common causes include software bugs, failing optical drive, or water ingress from the rear washer pipe leaking into the boot-mounted unit. Features like navigation, Bluetooth, or climate controls may stop working. Repair costs vary widely: software fixes are cheap, but hardware replacement runs €800-1,500.
Window regulator failure€150 - €350
Common wear item, window drops or operates slowly · more· less
Window regulators are a known weak point on the C6. The mechanism wears out causing the window to drop, operate slowly, or make grinding noises. Parts: €50-100. Labor: €100-250 per window. Not safety-critical but annoying when it happens.
High complexity, requires careful buying
The 2.7 TDI is a capable engine but the C6 platform has many potential failure points. The timing chain and gearbox (if Multitronic) are the big-ticket items. Stick to Tiptronic or manual gearboxes, verify timing chain service history, and avoid pre-2007 cars with first-gen injectors. Budget for diesel-specific maintenance (DPF, EGR) and find a good independent Audi specialist.
Pre-Purchase Inspection Checklist
General checks
Service history Complete records essential. Verify oil changes at proper intervals (not "longlife" - shorter is better for this engine).
Tires Check tread depth, age (date codes), and uneven wear patterns.
Cold start Must start engine completely cold. Listen for unusual sounds in first 30 seconds.
Test drive Minimum 30 minutes including city and highway driving to get everything up to temperature.
Specific for this vehicle
Cold start timing chain rattle Start engine completely cold and listen for rattle in first 1-30 seconds. Any prolonged rattle = tensioner issue. This is the most important check.
Check gearbox type Verify if Multitronic (CVT), Tiptronic, or manual. Avoid Multitronic if possible, especially pre-2008.
VCDS scan for fault codes Essential to check for injector faults, gearbox errors, DPF status, and timing-related codes. Ask seller to allow this before purchase.
Check for oil leaks Look under the car and around the engine for oil trails. Check valve cover area and front of engine near timing cover.
Test all MMI functions Navigate through menus, test navigation, Bluetooth, CD player. Check for freezing or slow response.
DPF regeneration status Ask about driving patterns. Short-trip-only cars likely have DPF issues. Check with VCDS for soot loading percentage.
Turbo boost test Drive hard and check for limp mode, hesitation, or boost-related warning lights.
Window operation Test all windows - listen for grinding, check speed of operation.
Multitronic clutch upgrade (5-plate to 7-plate)Ask dealer
Piezo injector updates (pre-2007 cars)Ask dealer
Takata airbag recall (varies by market)Verify with VIN
Contact Audi with VIN to check recall status. The timing chain tensioner had 7+ revisions - ask if the latest version was fitted. For Multitronic cars, verify if the 7-plate clutch upgrade was done.
Warranty Status
Factory warranty (2 years)Expired on all C6
Extended warranty optionsThird-party only
All C6 A6s are well outside factory warranty. Third-party warranties are available but often exclude known problem areas (timing chain, CVT). An independent pre-purchase inspection (€100-200) is better value than most warranty products for a car this age.
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.