The 2021 Audi S5 with the 3.0T V6 is generally solid, but shares the B9 platform's known weak points: transmission cooler leaks, carbon buildup on intake valves, and occasional catastrophic engine failures tied to defective piston rings and rod bearings—mostly seen in earlier 3.0T engines but still a concern.
EA839 3.0T Piston Ring / Rod Bearing Failure (Catastrophic Engine Damage)
Rare · high severity
Typical onset: 30,000-80,000 mi
Symptoms: Metallic knocking or rod knock at idle or acceleration, Excessive oil consumption (1+ qt per 1,000 mi), Check engine light with low oil pressure codes, Catastrophic failure—sudden loss of power, seized engine
Fix: Complete engine rebuild or replacement. Involves removing engine, replacing pistons, rings, rod bearings, mains, often crankshaft. 40-60 labor hours depending on extent of damage. Audi extended warranty on some VINs; verify eligibility before paying out of pocket.
Estimated cost: $15,000-25,000
Transmission Oil Cooler Leak (ZF 8HP)
Occasional · medium severity
Typical onset: 60,000-100,000 mi
Symptoms: Transmission fluid pooling under car, usually driver-side, Burnt transmission fluid smell, Harsh shifts or slipping if fluid level drops significantly, Pink or red fluid residue on undertray
Fix: Replace transmission oil cooler and lines. Requires partial removal of undertray and sometimes front bumper depending on access. 4-6 labor hours, includes fluid refill and system flush.
Estimated cost: $1,200-2,000
Carbon Buildup on Intake Valves (Direct Injection)
Common · medium severity
Typical onset: 60,000-90,000 mi
Symptoms: Rough idle, misfires at cold start, Loss of power, hesitation on acceleration, Check engine light with misfire codes (P030X), Increased fuel consumption
Fix: Walnut blasting intake valves. Remove intake manifold, manually clean each valve with crushed walnut media. 6-8 labor hours for all six cylinders. Preventive cleaning every 60-80k mi recommended.
Estimated cost: $800-1,400
Transmission Mount Failure
Occasional · low severity
Typical onset: 70,000-110,000 mi
Symptoms: Clunking or thudding on hard acceleration or deceleration, Excessive drivetrain movement felt through shifter or floorboard, Vibration at idle in Drive, Visible cracking or separation of rubber mount
Fix: Replace transmission mount(s). Often the rear or side mounts fail first. Requires lifting transmission slightly. 2-3 labor hours per mount.
Symptoms: Clunking or creaking from rear suspension over bumps, Wandering or vague steering feel at highway speeds, Uneven rear tire wear, Rear end feels loose or unstable in corners
Fix: Inspect and replace rear subframe bushings or axle mounts if worn. Some units affected by NHTSA recall for rear axle assembly—verify recall completion. 3-5 labor hours depending on which bushings need replacement.
Estimated cost: $800-1,500
Thermostat Housing / Coolant Flange Leaks
Occasional · medium severity
Typical onset: 50,000-90,000 mi
Symptoms: Coolant smell in cabin or under hood, Visible coolant residue on engine block near thermostat, Slow coolant loss, need to top off every few weeks, Overheating if leak progresses unchecked
Fix: Replace thermostat housing and associated o-rings/gaskets. Often plastic flanges crack. 2-4 labor hours depending on access and whether supercharger intake needs partial removal.
Estimated cost: $600-1,100
Owner tips
Use Top Tier fuel and consider occasional Italian tune-ups (hard pulls to redline) to minimize carbon buildup on intake valves.
Monitor oil consumption closely—if you're adding more than 1 qt between changes, document it and investigate immediately; engine replacement under warranty is time-sensitive.
Verify any open recalls (especially rear axle and lighting) before purchase; get documentation of completion.
Change transmission fluid every 50-60k mi despite Audi's 'lifetime' claim; ZF 8HP runs cooler and shifts better with fresh fluid.
Excellent driver's car when maintained, but the low-probability catastrophic engine failure risk and carbon buildup maintenance make CPO or extended warranty highly advisable—buy only with full service records and oil consumption history.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.
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Volkswagen Group of America, Inc. (Volkswagen) is recalling certain 2021 Audi A8, RS7, RS6 Avant, RS5 Sportback, RS5 Coupe, Q8, Q7, Q5 Sportback, S4 Sedan, Q5, A7, A6, A6 Allroad, A5 Sportback, A5 Coupe, A5 Cabrioleet, A4 Sedan, A4 Allroad, E-Tron Sportback Quattro, SQ7, S5 Cabriolet, E-Tron Quattro, SQ8, SQ5 Sportback, SQ5, S8, S7, S6 Sedan, S5 Sportback, S5 Coupe, 2022 E-Tron GT, and 2021-2022 RSQ8 vehicles. Due to a software issue, a blank or black screen may be displayed instead of the rearview camera image when the vehicle is placed in reverse gear. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 111, "Rear Visibility."
Consequence: A blank rearview camera display can reduce the driver's rear visibility, increasing the risk of a crash.
Remedy: Dealers will update the infotainment unit software, free of charge. Owner notification letters were mailed October 25, 2022. Owners may contact Audi's customer service at 1-800-253-2834. Volkswagen's number for this recall is 91DZ.
TIRES · 22V034000
2022-01-26
Volkswagen Group of America, Inc. (Audi) is recalling certain 2019-2021 Audi A5 Sportback, RS5 Coupe, RS5 Sportback, S5 Sportback, 2020-2021 A4 Allroad, A4 Sedan, A5 Cabriolet, A5 Coupe, A6 Allroad, A6 Sedan, A7, A8, Q5, S4 Sedan, S5 Coupe, S5 Cabriolet, S6 Sedan, S7, S8, SQ5, 2021 Q5 Sportback, Q7, Q8, RS6 Avant, RS7, RSQ8, SQ5 Sportback, SQ7, and SQ8 vehicles. The rear axle alignment may not have been inspected after the repairs for Recall 21V-295 (42L1) were performed.
Consequence: Rear axle misalignment may cause premature or uneven tire wear, increasing the risk of a crash.
Remedy: Dealers will inspect the rear axle, adjust the alignment as necessary, and replace any prematurely or unevenly worn tires, free of charge. Owner notification letters were mailed March 3, 2022. Owners may contact Audi customer service at 1-800-253-2834. Audi's number for this recall is 42L5.
SEAT BELTS:REAR/OTHER:RETRACTOR · 21V606000
2021-08-05
Volkswagen Group of America, Inc. (Volkswagen) is recalling certain 2021 Volkswagen ID4, Audi A4 Allroad, A4 Sedan, A5 Cabriolet, A5 Coupe, A5 Sportback, A6 Allroad, A6 Sedan, A7, A8, E-Tron Quattro, E-Tron Sportback Quattro, Q3, Q5, Q5 Sportback, Q7, Q8, RS5 Sportback, RS5 Coupe, RS6 Avant, RS7, RSQ8, S4 Sedan, S5 Cabriolet, S5 Coupe, S5 Sportback, S6 Sedan, S7, S8, SQ5, SQ5 Sportback, SQ7, SQ8, and 2021-2022 S3 Sedan vehicles. The rear seat belt automatic locking retractors may deactivate early, which can prevent the child restraint system from securing properly. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 208, "Occupant Crash Protection."
Consequence: An unsecured child restraint system can increase the risk of injury during a crash.
Remedy: Dealers will inspect, and replace as necessary, the middle-rear seat belt assemblies, free of charge. Owner notification letters were mailed August 27, 2021. Owners may contact Volkswagen customer service at 1-800-893-5298 and Audi customer service at 1-800-253-2834. Volkswagen's numbers for this recall are 69CR (VW) and 69CS (Audi).
Volkswagen Group of America, Inc. (Audi) is recalling certain 2021 Q7, Q8, Q5 Sportback, SQ5 Sportback, RS6 Avant, RS7, RS Q8, 2020-2021 Audi S6 sedan, Q5, A8, S8, A7, A6 Allroad, A5 Cabriolet, A4 sedan, A4 Allroad, SQ5, S7, A6 sedan, S5 coupe, S4 sedan, S5 Cabriolet, A5 coupe, 2019-2021 RS5 coupe, A5 Sportback, S5 Sportback, RS5 Sportback vehicles. The lock nut on the trailing arm of the rear axle may break due to stress corrosion.
Consequence: A broken lock nut may misalign the rear axle, causing a loss of control and increasing the risk of a crash.
Remedy: Dealers will replace the lock nuts and, if necessary, the associated bolts, free of charge. Owner notification letters were mailed June 4, 2021. Owners may contact Audi customer service at 1-800-253-2834. Audi's number for this recall is 42L1.
EXTERIOR LIGHTING:TAIL LIGHTS · 20V737000
2020-11-25
Volkswagen Group of America, Inc. (Audi) is recalling certain 2021 Audi RS5 Sportback, 2020-2021 Audi A5 Sportback, and S5 Sportback vehicles. The wiring harness for the rear lights could be missing the anti-abrasion protection in the area of the spare wheel well.
Consequence: Without the scuff protection, the wires may become damaged during a rear crash, disabling the doors from being opened from the outside, causing a loss of hazard lights, and increasing the risk of injury.
Remedy: Audi will notify owners, and dealers will apply scuff protection, free of charge. The recall began January 21, 2021. Owners may contact Audi customer service at 1-800-253-2834. Audi's number for this recall is 97EU.
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