Audi A5/S5/RS5 B9 Reliability Guide (U.S. Market and Global Overview)
The Audi A5, S5, and RS5 B9 lineup represents the sportier side of the A4 platform, combining coupe styling, Quattro grip, and strong performance. Introduced for the 2018 model year in the U.S., the B9 generation brought new engines, lighter construction, and a fully digital interior.
While these models are praised for refinement and driving dynamics, long-term ownership has highlighted a few recurring reliability concerns. This guide provides a detailed look at what to expect from each engine variant and how to keep your B9-series Audi running smoothly for years to come.
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Overall Reliability of the Audi A5/S5/RS5 B9
Across the B9 range, reliability is generally above average, provided maintenance schedules are followed carefully.
Audi made significant improvements over the B8 generation—particularly in reducing oil consumption and improving electronics—but minor sensor faults, cooling system leaks, and turbo wear can still appear over time. Owners who perform regular oil changes and software updates typically experience few serious problems.
Common Issues Across All B9 A5/S5/RS5 Models
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MMI and Virtual Cockpit glitches: Freezes or black screens due to software bugs (usually resolved with updates).
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Coolant leaks: Commonly from plastic thermostat or water pump housings.
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Electrical sensors: Occasional check-engine lights from failed O2, boost, or cam sensors.
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DSG/S-Tronic hesitation: Jerky or delayed shifting in early production cars.
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Carbon deposits: A result of direct injection, particularly noticeable after 60,000+ miles.
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Turbo wastegate rattle: A minor but frequent noise on higher-mileage 2.0T models.
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Adaptive cruise or lane assist errors: Often due to radar misalignment or camera calibration issues.
Engine-by-Engine Reliability Breakdown
2.0 TFSI (A5 B9)
The A5’s 2.0-liter turbocharged four-cylinder is one of Audi’s most widely used engines. It’s efficient, smooth, and capable—but requires proactive care.
Typical issues:
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Early signs of oil seepage at valve cover or front seals.
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Water pump and thermostat failures due to plastic components.
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Turbo actuator faults causing underboost codes.
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Intake valve carbon build-up.
Maintenance tips:
Stick to 5,000-mile oil intervals with VW 508.00-approved oil. Inspect coolant components every 30,000 miles, and consider walnut blasting the intake valves around 60,000 miles. Regular maintenance makes this engine very durable.
3.0 TFSI Turbo (S5 B9)
Replacing the older supercharged V6, this turbocharged 3.0-liter engine delivers strong torque and improved fuel economy. It’s generally reliable but not immune to a few age-related problems.
Typical issues:
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PCV valve or crankcase breather failures causing vacuum leaks.
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Oil leaks from cam covers or rear main seal in high-mileage cars.
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DSG/S-Tronic mechatronic issues (rare, mostly early models).
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Carbon accumulation over time.
Maintenance tips:
Use premium fuel and change oil every 5,000 miles. Replace the DSG fluid and filter every 40,000 miles, and apply all available ECU/TCU updates. With consistent care, the 3.0T easily exceeds 150,000 miles of reliable service.
2.9 TFSI Biturbo (RS5 B9)
The RS5’s twin-turbo V6 offers exceptional power with improved efficiency compared to the old V8, but it’s a more complex and tightly packaged system.
Typical issues:
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Turbocharger oil feed line leaks if oil change intervals are extended.
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Heat-related wear on hoses and intercooler components.
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PCV and crankcase pressure issues leading to rough idle.
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Carbon build-up from direct injection and short-trip driving.
Maintenance tips:
Frequent oil changes (every 5,000 miles), careful warm-up and cooldown habits, and occasional intake cleaning are essential. Avoid cars with heavy tuning unless backed by maintenance records and upgraded cooling systems. A well-kept RS5 B9 is both fast and dependable.
Other Reliability Considerations
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Suspension components: Control arm bushings and adaptive dampers can wear faster on heavier S/RS models.
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Brakes: Performance models use larger rotors that can warp under aggressive use—use OEM or high-quality replacements.
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Interior electronics: Screen delamination and HVAC panel failures are rare but possible.
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Exterior trim: Soft paint and aluminum body panels can show wear if not protected regularly.
What to Inspect Before Buying a Used A5, S5, or RS5 B9
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Confirm all recall and service campaigns are complete.
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Inspect for coolant leaks near the thermostat housing.
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Check for rough idle or whistling noises from the PCV system.
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Test the infotainment system for responsiveness and Bluetooth connectivity.
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Ensure DSG/S-Tronic shifts smoothly and has fluid change records.
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Listen for turbo noise or boost flutter under acceleration.
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Look for signs of tuning or aftermarket modifications.
Verdict: Is the Audi A5/S5/RS5 B9 Reliable?
The Audi B9 platform represents a solid leap in reliability over the B8 generation.
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The A5’s 2.0T engine is dependable and efficient when serviced on time.
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The S5’s 3.0T strikes a near-perfect balance between performance and longevity.
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The RS5’s 2.9 Biturbo offers supercar performance in a practical package—but demands diligent care.
Overall, the A5/S5/RS5 B9 delivers strong reliability and refinement for its class. With consistent maintenance and up-to-date software, these models provide a rewarding and long-lasting ownership experience.
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