2021 Audi S6 Problems: 4 Issues Every Owner Should Know

2021 Audi S6 Problems: 4 Issues Every Owner Should Know | Au7o

All 4 Known Issues

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172 owners

On the 2013-2024 Audi S6 4.0T, the twin-turbo 4.0T V8 in the S6 uses coolant lines routed to each turbocharger that are prone to cracking and leaking. The lines are difficult to access and failure can cause rapid coolant loss.

This issue also affects: Audi A8, Audi RS6, Audi RS7

Common Symptoms

Coolant loss
Overheating after spirited driving
Coolant smell from engine bay
Steam from turbo area
Low coolant warning
White smoke from exhaust

How to Fix

Replace turbo coolant lines with updated silicone or reinforced lines. Inspect all coolant connections in the turbo area.

What Owners Are Using

Parts and tips from 172+ owners who fixed this issue

UpgradeTurbo Coolant Line Kit (Genuine Audi #079121481E)
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Typical repair cost:$800 - $2,500

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172+ owners have reported this issue

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Community Reported

High Confidence172 reportsLast reported by owners Mar 2026Reviewed Mar 2026

Community Reported

146 owners

On the 2013-2024 Audi S6, the S6 adaptive air suspension struts develop air leaks at the rubber bladders and valve blocks, causing the car to sag overnight or drop to one corner. Compressor overwork from compensating shortens its life.

Common Symptoms

Vehicle sagging overnight
Uneven ride height
Suspension warning light
Compressor running constantly
Rough ride quality
Nose diving under braking

How to Fix

Replace leaking air struts. Consider replacing compressor if it runs excessively. Aftermarket struts are available at lower cost.

What Owners Are Using

Parts and tips from 146+ owners who fixed this issue

UpgradeFront Air Strut Assembly (Arnott #AS-3262)
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Typical repair cost:$800 - $3,000

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146+ owners have reported this issue

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Community Reported

High Confidence146 reportsLast reported by owners Mar 2026Reviewed Mar 2026

Community Reported

294 owners

On the 2013-2024 Audi S6 4.0T, the S6 4.0T twin-turbo V8 develops carbon deposits on all eight intake valves. The twin-turbo layout and high heat make carbon accumulation aggressive, with symptoms appearing as early as 30,000 miles.

This issue also affects: Audi A8, Audi RS6, Audi RS7

Common Symptoms

Rough idle
Misfires
Power loss
Hesitation at low RPM
Check engine light
Uneven cylinder performance

How to Fix

Walnut blast all eight intake runners. Dual-injection models (2019+) are less affected.

What Owners Are Using

Parts and tips from 294+ owners who fixed this issue

UpgradeCatch Can Kit for 4.0T (034Motorsport #034-101-1015)
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Typical repair cost:$600 - $1,400

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294+ owners have reported this issue

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Community Reported

High Confidence294 reportsLast reported by owners Mar 2026Reviewed Mar 2026

On the 2019-2025 Audi S6, late-model Audi vehicles including the S6 were recalled for a software error that can prevent the rearview camera image from displaying. This creates a visibility and back-over prevention risk when reversing.

Common Symptoms

Rearview camera image does not display
Blank or unavailable backup camera screen
Intermittent camera operation when shifting into reverse
MMI display shows no rear camera image

How to Fix

Confirm whether recall 25V900000 applies to the vehicle and have the dealer perform the software update. Diagnosis typically involves checking MMI/camera control module software level and verifying image output after reprogramming.

What Owners Are Using

Parts and tips from 0+ owners who fixed this issue

TipIf the camera image is intermittent, document the failure with photos/video before dealer visit to help verify the software-related condition.
TipCheck for pending MMI or camera module updates whenever backup camera behavior changes after battery replacement or low-voltage events.

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0+ owners have reported this issue

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NHTSA Verified

High Confidence0 reportsLast reported by owners Invalid DateReviewed Invalid Date

⚠️NHTSA Recalls11 recalls

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."

Campaign #25V90000019/12/2025

EQUIPMENT:ELECTRICAL:INFOTAINMENT:VIDEO (TOUCH)SCREEN/MONITOR/UNIT

Volkswagen Group of America, Inc. (Audi) is recalling certain 2021-2022 AUDI A8, A6 Allroad, E-TRON Quattro, 2022 S3, RSQ8, RS7, RS6 Avant, Q8, Q7, Q3, E-TRON Sportback Quattro, S5 Cabriolet, E-TRON GT, S5 Sportback, A7, A6, A5 Sportback, A5 Cabriolet, A4, A4 Allroad, A3, S8, SQ7, SQ8, S6, and S4 vehicles. The infotainment main unit may become damaged internally when the vehicle is shut off, resulting in an inoperative rearview camera display the next time the vehicle is started. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 111, "Rear Visibility."

Campaign #22V80600026/10/2022

ELECTRICAL SYSTEM

Volkswagen Group of America, Inc. (Audi) is recalling certain 2020-2022 Audi S7, S6 Sedan, A6 Allroad, 2021-2022 RS7, RS6 Avant, 2019-2022 A7, and A6 Sedan vehicles. Liquid spilled in the rear seat may penetrate and cause the gateway control module to shut down.

Campaign #22V86100021/11/2022

ELECTRICAL SYSTEM:INSTRUMENT PANEL:FUEL GAUGE:FUEL LEVEL FLOAT/SENSOR/SENDING UNIT

Volkswagen Group of America, Inc. (Audi) is recalling certain 2021-2022 RS6 Avant and RS7, 2020-2022 A6 Allroad, S6 Sedan, and S7, and 2019-2022 A6 Sedan and A7 vehicles. The fuel level sender may stick, causing an inaccurate fuel level reading to be displayed on the instrument cluster.

Campaign #22V15500014/03/2022

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."

Campaign #21V60600005/08/2021

+ 6 more recalls. Check all on NHTSA.gov

Enter your VIN at NHTSA.gov to check recalls specific to your vehicle.

Frequently Asked Questions

What are the most common Audi S6 problems?

According to Au7o's analysis of 612+ owner reports, the 2021-2021 Audi S6 has 4 documented issues. The most frequently reported are: 4.0T Turbo Coolant Line Failure, Adaptive Air Suspension Strut Leaks, 4.0T Direct Injection Carbon Buildup. Of these, 2 are rated critical and should be addressed promptly.

Is the Audi S6 reliable?

The 2021-2021 Audi S6 has 4 known issues documented across 612+ owner reports. 2 issues are rated critical: 4.0T Turbo Coolant Line Failure and Adaptive Air Suspension Strut Leaks. Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.

How much does it cost to fix common Audi S6 problems?

Repair costs for known Audi S6 issues range from $600 to $3,000, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, 4.0T Turbo Coolant Line Failure, typically costs $800-$2,500 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.

What is the 2013-2024 Audi S6 4.0T Turbo Coolant Line Failure?

The twin-turbo 4.0T V8 in the S6 uses coolant lines routed to each turbocharger that are prone to cracking and leaking. The lines are difficult to access and failure can cause rapid coolant loss. Repairs typically run $800-$2,500. Severity: high.

What is the 2013-2024 Audi S6 Adaptive Air Suspension Strut Leaks?

The S6 adaptive air suspension struts develop air leaks at the rubber bladders and valve blocks, causing the car to sag overnight or drop to one corner. Compressor overwork from compensating shortens its life. Repairs typically run $800-$3,000. Severity: high.

What is the 2013-2024 Audi S6 4.0T Direct Injection Carbon Buildup?

The S6 4.0T twin-turbo V8 develops carbon deposits on all eight intake valves. The twin-turbo layout and high heat make carbon accumulation aggressive, with symptoms appearing as early as 30,000 miles. Repairs typically run $600-$1,400. Severity: medium.

What is the 2019-2025 Audi S6 Rearview Camera Image Failure From Software Error?

Late-model Audi vehicles including the S6 were recalled for a software error that can prevent the rearview camera image from displaying. This creates a visibility and back-over prevention risk when reversing. Severity: medium.

2021 Audi S6 Problems: 4 Issues Every Owner Should Know

All 4 Known Issues

2013-2024 Audi S6: 4.0T Turbo Coolant Line Failure#

Common Symptoms

How to Fix

What Owners Are Using

Research This Issue

2013-2024 Audi S6: Adaptive Air Suspension Strut Leaks#

Common Symptoms

How to Fix

What Owners Are Using

Research This Issue

2013-2024 Audi S6: 4.0T Direct Injection Carbon Buildup#

Common Symptoms

How to Fix

What Owners Are Using

Research This Issue

2019-2025 Audi S6: Rearview Camera Image Failure From Software Error#

Common Symptoms

How to Fix

What Owners Are Using

Research This Issue

Other Audi Models

Frequently Asked Questions

What are the most common Audi S6 problems?

Is the Audi S6 reliable?

How much does it cost to fix common Audi S6 problems?

What is the 2013-2024 Audi S6 4.0T Turbo Coolant Line Failure?

What is the 2013-2024 Audi S6 Adaptive Air Suspension Strut Leaks?

What is the 2013-2024 Audi S6 4.0T Direct Injection Carbon Buildup?

What is the 2019-2025 Audi S6 Rearview Camera Image Failure From Software Error?