2018 model year · 2,600+ owner reports · Updated May 2026
According to Au7o's analysis of 2,600+ owner reports, the 2018 Audi A6 has 6 documented known issues. No issues are rated critical, indicating generally reliable ownership. The most commonly reported issue is Air Suspension Compressor Failure with 1,400 owner reports. Across all issues, repair costs range from $80 to $2,500. DIY maintenance guides at au7o.io.
On the 2012-2018 Audi A6 3.0T, the 3.0T supercharged V6 in the C7 A6 develops bearing wear in the supercharger nose cone assembly. The front bearing supporting the supercharger rotor shaft degrades over time, causing a whining noise that increases with RPM. If left unaddressed, the bearing can seize and destroy the supercharger internally.
Replace the supercharger nose cone bearing assembly. This can be done without removing the entire supercharger by accessing the nose cone from the front. Updated bearings from aftermarket suppliers like JHM and 034 Motorsport are more durable than OEM. Full supercharger replacement is $3,000-$5,000 at dealer but nose cone repair is $500-$1,200.
Parts and tips from 1,200+ owners who fixed this issue
On the 2005-2023 Audi A6, water pump failures are common across all A6 generations due to plastic impeller degradation and seal leaks. Audi uses plastic impellers that crack or disintegrate over time (typically 80,000-120,000 miles), causing coolant leaks and overheating. The water pump is often driven by the timing belt or timing chain, so replacement is recommended during timing service to save labor. Thermostat housings also crack due to heat cycling, causing coolant leaks and erratic temperature readings. Symptoms include coolant leaks under the car, overheating in traffic, temperature gauge fluctuations, and coolant warning lights. Ignoring a failed water pump can lead to severe engine overheating, warped cylinder heads, and blown head gaskets ($3,000-$5,000 repair). Some models have electric auxiliary water pumps that also fail, causing poor heater performance.
Replace water pump AND thermostat together ($800-$1,500 with labor). Always use OEM or high-quality aftermarket parts (Rein, Hepu)—cheap pumps fail within 20,000 miles. If water pump is timing belt/chain driven, replace during timing service to save labor. Flush cooling system and refill with OEM Audi G12++ or G13 coolant (do NOT mix types). Inspect coolant hoses and replace if cracked. If auxiliary electric water pump fails, replace separately ($300-$600). Monitor coolant level weekly and address leaks immediately to prevent overheating damage.
Parts and tips from 0+ owners who fixed this issue
On the 2011-2023 Audi A6, all direct-injection engines in the A6 (2.0T TFSI and 3.0T supercharged) suffer from carbon buildup on intake valves due to lack of fuel washing over the valves. In port-injection engines, fuel sprays onto intake valves and cleans them, but direct injection sprays fuel directly into the cylinder, leaving valves exposed to crankcase oil vapors from the PCV system. Over 60,000-100,000 miles, hard carbon deposits accumulate on the back of intake valves, restricting airflow and causing rough idle, misfires, loss of power, and poor fuel economy. The only permanent fix is walnut blasting—a process where crushed walnut shells are blasted through the intake to remove carbon without damaging valves. Symptoms worsen in stop-and-go driving. Some engines develop such severe buildup that valves cannot close properly, requiring valve replacement. AudiWorld members recommend walnut blasting every 60,000-80,000 miles as preventive maintenance.
WALNUT BLASTING: Remove intake manifold and blast crushed walnut shells through intake ports to remove carbon deposits ($600-$1,200). This is a 4-6 hour job requiring specialized equipment—DIY is not recommended. Dealers charge $1,000-$1,500; independent Audi specialists charge less. Repeat every 60,000-80,000 miles as preventive maintenance. PREVENTION: Use high-quality Top Tier gasoline, add Liqui Moly Intake Valve Cleaner every oil change, and perform occasional "Italian tune-up" (spirited highway driving to burn off carbon). Catch can installation ($300-$500) filters crankcase vapors and dramatically reduces carbon buildup.
Parts and tips from 0+ owners who fixed this issue
On the 2012-2018 Audi A6, the Positive Crankcase Ventilation (PCV) valve in C7 A6 models (2012-2018) with 2.0T and 3.0T engines is prone to failure, causing rough idle, oil consumption, and check engine lights. The PCV system recirculates crankcase gases back into the intake to burn them, but the valve diaphragm tears or the valve clogs with oil sludge over time. A failed PCV valve creates excessive vacuum in the crankcase, pulling oil past seals and causing leaks. It also disrupts air/fuel ratio, causing rough idle, hesitation, and poor fuel economy. Replacing the PCV valve is a simple 30-minute DIY job that costs $80-$150 for OEM parts. Many owners replace the PCV valve every 40,000-60,000 miles as preventive maintenance to avoid oil consumption issues. A clogged PCV valve also contributes to carbon buildup on intake valves.
Replace PCV valve with OEM Audi part ($80-$150). The valve is located on the valve cover and takes 30 minutes to replace (DIY-friendly). Disconnect hose, twist valve counterclockwise, and install new valve. No special tools required. While you're there, inspect PCV hoses for cracks and replace if necessary ($20-$50). If oil consumption persists after PCV replacement, piston rings may be worn (see oil consumption issue). Replace PCV valve every 40,000-60,000 miles as preventive maintenance—cheap insurance against bigger problems.
Parts and tips from 0+ owners who fixed this issue
On the 2012-2018 Audi A6, c7 A6 models equipped with adaptive air suspension experience compressor failure, typically between 60,000 and 100,000 miles. The compressor overworks to compensate for slow leaks in aging air springs, eventually burning out its motor or relay. The car sags overnight and takes increasingly longer to level on startup.
Replace the air suspension compressor. Check all four air springs for leaks before replacing the compressor, as a leaking spring will kill a new compressor quickly. The compressor relay should be replaced at the same time. Consider replacing air springs proactively if over 80,000 miles.
Parts and tips from 1,400+ owners who fixed this issue
On the 2005-2023 Audi A6, the Audi A6 is prone to various electrical gremlins across all generations, including window regulator failures, door lock actuator failures, MMI/infotainment glitches, and battery drain issues. Window regulators fail due to weak plastic clips in the mechanism, causing windows to drop into the door or move slowly. Door lock actuators wear out, causing doors to unlock randomly, fail to lock, or make grinding noises. MMI (Multi Media Interface) infotainment systems freeze, reboot randomly, or display "SAFE" mode. Battery drain issues (parasitic draw) are common, leaving the car dead after sitting for a few days. Many electrical issues are caused by aging control modules, corroded connectors, or software bugs. While frustrating, most electrical issues are not safety-critical and can be addressed individually as they arise.
Window regulator replacement: $300-$600 per window (DIY $150-$250 with aftermarket kit). Order regulator with metal clips, not plastic. Door lock actuator: $200-$400 per door at dealer, DIY $50-$100 per actuator (1-hour job). MMI/infotainment glitches: Perform hard reset (hold power + volume up for 10 seconds). If that fails, Audi dealer can update software or replace MMI unit ($1,000-$2,500). Battery drain: Have dealer perform parasitic draw test to identify faulty module. Common culprits: trunk electronics, MMI, comfort control module. Address issues as they arise—most are minor annoyances, not showstoppers.
Parts and tips from 0+ owners who fixed this issue
BACK OVER PREVENTION: SENSING SYSTEM: CAMERA
Volkswagen Group of America, Inc. (Audi) is recalling certain 2019-2026 vehicles. Please see the recall report for a complete list of models. A software error may prevent the rearview camera image from displaying as intended. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 111, "Rear Visibility."
SEAT BELTS:REAR/OTHER:RETRACTOR
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."
TIRES
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.
AIR BAGS
Volkswagen Group of America, Inc. (Audi) is recalling certain 2021 Audi RS6 Avant, RS7, 2020-2021 A6 Allroad, S6 Sedan, S7, 2019-2021 A6 Sedan, and A7 vehicles. The score line on the passenger air bag may not have been manufactured correctly.
ELECTRICAL SYSTEM
Volkswagen Group of America, Inc. (Audi) is recalling certain 2021 Audi A6 Allroad, Q7, RS6 and RS7 vehicles. The electrical connector can detach from the door crash sensor in either of the front doors.
+ 11 more recalls. Check all on NHTSA.gov
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According to Au7o's analysis of 2,600+ owner reports, the 2018-2018 Audi A6 has 6 documented issues. The most frequently reported are: Air Suspension Compressor Failure, Supercharger Nose Cone Bearing Wear, Water Pump and Thermostat Failure (Overheating). None are rated critical, but regular maintenance is recommended.
The 2018-2018 Audi A6 has 6 known issues documented across 2,600+ owner reports. No issues are rated critical, suggesting generally good reliability. Regular maintenance following the manufacturer's schedule helps prevent many common problems.
Repair costs for known Audi A6 issues range from $80 to $2,500, depending on the specific problem and whether you choose DIY or professional repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.
C7 A6 models equipped with adaptive air suspension experience compressor failure, typically between 60,000 and 100,000 miles. The compressor overworks to compensate for slow leaks in aging air springs, eventually burning out its motor or relay. The car sags overnight and takes in… Repairs typically run $800-$2,500. Severity: medium.
The 3.0T supercharged V6 in the C7 A6 develops bearing wear in the supercharger nose cone assembly. The front bearing supporting the supercharger rotor shaft degrades over time, causing a whining noise that increases with RPM. If left unaddressed, the bearing can seize and destro… Repairs typically run $500-$2,500. Severity: medium.
Water pump failures are common across all A6 generations due to plastic impeller degradation and seal leaks. Audi uses plastic impellers that crack or disintegrate over time (typically 80,000-120,000 miles), causing coolant leaks and overheating. The water pump is often driven by… Repairs typically run $800-$1,500. Severity: medium.
All direct-injection engines in the A6 (2.0T TFSI and 3.0T supercharged) suffer from carbon buildup on intake valves due to lack of fuel washing over the valves. In port-injection engines, fuel sprays onto intake valves and cleans them, but direct injection sprays fuel directly i… Repairs typically run $600-$1,500. Severity: medium.
The Positive Crankcase Ventilation (PCV) valve in C7 A6 models (2012-2018) with 2.0T and 3.0T engines is prone to failure, causing rough idle, oil consumption, and check engine lights. The PCV system recirculates crankcase gases back into the intake to burn them, but the valve di… Repairs typically run $80-$300. Severity: low.
The Audi A6 is prone to various electrical gremlins across all generations, including window regulator failures, door lock actuator failures, MMI/infotainment glitches, and battery drain issues. Window regulators fail due to weak plastic clips in the mechanism, causing windows to… Repairs typically run $100-$2,500. Severity: low.
Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.
