The 2021 Audi A4 with the 2.0T engine is showing concerning early oil consumption patterns tied to piston ring issues, a problem that plagued earlier B9 generations and appears to persist in some 2021 builds. Otherwise a solid platform, but that engine defect can be catastrophic if ignored.
Excessive Oil Consumption / Piston Ring Failure
Occasional · high severity
Typical onset: 30,000-70,000 mi
Symptoms: Burning more than 1 quart per 1,000 miles, Blue smoke on cold starts or hard acceleration, Low oil warning lights between service intervals, Carbon buildup on intake valves exacerbating the problem
Fix: Full engine teardown to replace piston rings and address cylinder bore glazing. Some cases require oversized pistons or short block replacement if cylinder wear is excessive. 18-24 labor hours for ring job, 28-35 hours for short block swap. Audi has extended warranty coverage on some VINs—check before paying out of pocket.
Estimated cost: $4,500-8,500
Thermostat Housing Coolant Leak
Common · medium severity
Typical onset: 50,000-90,000 mi
Symptoms: Coolant smell in cabin or under hood, Slow coolant loss, puddles on passenger side of engine bay, Temperature fluctuations or overheating in severe cases
Fix: Replace plastic thermostat housing and associated O-rings. Common failure point on EA888 Gen 3 engines. 2.5-3.5 labor hours including coolant flush.
Estimated cost: $600-950
Transmission Mount Failure
Common · low severity
Typical onset: 40,000-80,000 mi
Symptoms: Clunking on 1-2 upshifts or during throttle tip-in, Excessive driveline vibration at idle in Drive, Visible tearing or fluid weeping from dogbone mount
Fix: Replace pendulum mount (dogbone) under transmission. Very common wear item on MQB platform, especially with spirited driving. 1.5-2 labor hours.
Estimated cost: $350-550
Turbocharger Wastegate Rattle
Occasional · medium severity
Typical onset: 60,000-100,000 mi
Symptoms: Rattling noise on cold starts that disappears when warm, Reduced boost pressure or limp mode in advanced cases, P0299 or P0234 turbo underboost/overboost codes
Fix: Wastegate actuator arm wears in the housing causing play. Some can be adjusted, most require turbo replacement. 6-8 labor hours for turbo R&R on EA888.
Estimated cost: $1,800-3,200
Water Pump Failure (Electric Auxiliary)
Occasional · medium severity
Typical onset: 50,000-90,000 mi
Symptoms: Coolant warning light with no visible leak, Insufficient heating or overcooling, Whining or buzzing noise from front of engine
Fix: The auxiliary electric water pump (heater circuit) fails more often than the mechanical pump. Replace pump and bleed system. 2-3 labor hours.
Estimated cost: $650-1,100
Rear Axle Differential Mount Bushing Failure
Common · low severity
Typical onset: 50,000-100,000 mi
Symptoms: Clunking from rear on acceleration or deceleration, Vibration felt through floor at highway speeds, Visible rubber deterioration or oil soaking on subframe bushings
Fix: Replace rear differential carrier bushings or entire rear subframe mounts depending on damage. Part of 2021 NHTSA recall for some VINs (check), otherwise routine wear. 3-5 labor hours depending on rust and bushing press tooling.
Estimated cost: $700-1,400
Owner tips
Check oil level every 500-1,000 miles religiously—oil consumption issues creep up suddenly and starving the engine destroys it fast
Verify if your VIN is covered under Audi's extended warranty for piston ring consumption (settlement class from B8/B9 defects)
Use Top Tier fuel and occasional Italian tune-ups to minimize carbon buildup on direct-injection intake valves
Budget for walnut blasting intake valves every 50,000-60,000 miles ($500-800) if you're keeping it long-term
Solid daily driver if the piston rings are good—get a pre-purchase oil consumption test or walk away; one bad engine rebuild costs more than the depreciation you're saving.
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.
Fitment notes: AGM battery required for start-stop system; located under trunk floor
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Control Modules — 2021 Audi A4
Every control module on the 2018-2023 Audi A4 — where it lives, replacement time, and what it takes to program a replacement. Modules marked dealer / factory tool won't work after a part swap alone — budget for programming.
📍 Rear cargo area, left side behind trim (if factory tow package equipped)
🔧 VCDS or Autel
⚠️ Trailer detection and lighting functions. Most aftermarket tools can enable/code.
Rear View Camera Control Module (RVC)0.6 hr R&Raftermarket tool +0.2 hr▸ programming details
📍 Rear liftgate or bumper, integrated with camera or separate module in cargo area
🔧 VCDS or Autel
⚠️ Calibration lines may require coding. Basic function usually plug-and-play.
Aftermarket tool coverage varies by software version and vehicle build — treat "aftermarket tool" rows as "usually possible" and verify against your tool maker's coverage list before promising a customer. Spot a wrong location or hour? Tell us — corrections ship fast here.
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.
Vehicle Info — 2021 Audi A4
Performance
Horsepower
201hp
Torque
236lb-ft
0–60 mph
5.6sec
Quarter mile
14.2sec
Top speed
130mph
Fuel economy (EPA)
City
24mpg
Highway
31mpg
Combined
27mpg
Fuel
Premium Gasoline
Capability & size
Curb weight
3,858lb
Seating
5seats
EPA class
Compact Cars
Wiper blades
B9 generation facelift (2020-2023). Sedan body style has no rear wiper.
Size-standard part numbers — verify your connector type before buying. Rear blades are model-specific; check the package's vehicle list.
Fuel economy figures are EPA data via fueleconomy.gov (median across matching trims). Performance figures are compiled estimates for the 2021 Audi A4 2.0L I4 TFSI and can vary by trim.
🔧 Built by master technician Chris Hackleman · Master Technician · 20+ years.