2018 Audi S7 Problems: 4 Issues Every Owner Should Know

2018 model year · 468+ owner reports · Updated May 2026

According to Au7o's analysis of 468+ owner reports, the 2018 Audi S7 has 4 documented known issues, with 2 rated critical. The most serious are 4.0T Biturbo Coolant Line and Thermostat Failure ($900-$2,800 repair) and Air Suspension Compressor and Strut Failure ($1,000-$3,500 repair). The most commonly reported issue is 4.0T Biturbo Coolant Line and Thermostat Failure with 257 owner reports. Across all issues, repair costs range from $900 to $3,500. DIY maintenance guides at au7o.io.

All 4 Known Issues

Community Reported

257 owners

On the 2012-2024 Audi S7 4.0T, the S7 shares the 4.0T biturbo V8 cooling system issues with turbo coolant lines cracking under heat cycling. The thermostat housing also cracks, causing slow coolant loss that is hard to detect.

This issue also affects: Audi A3, Audi A6, Audi A8

Common Symptoms

Gradual coolant loss
Overheating during aggressive driving
Steam from engine bay
Low coolant warning
Sweet smell under hood
Temperature gauge fluctuation

How to Fix

Replace turbo coolant lines and thermostat housing. Use updated reinforced lines if available.

What Owners Are Using

Parts and tips from 257+ owners who fixed this issue

UpgradeTurbo Coolant Line Set (Genuine Audi #079121481F)
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Typical repair cost:$900 - $2,800

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257+ owners have reported this issue

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Community Reported

High Confidence257 reportsLast reported by owners Mar 2026Reviewed Mar 2026

Community Reported

211 owners

On the 2012-2024 Audi S7, the S7 adaptive air suspension system is prone to compressor burnout and strut bladder leaks. The sportback body style adds weight stress on rear struts. Compressor failures are often preceded by strut leaks overworking the pump.

Common Symptoms

Car sitting low on one corner
Suspension fault warning
Compressor noise or overheating
Bouncy ride
Uneven tire wear
Delayed ride height adjustment

How to Fix

Replace air struts and compressor. Check all air lines for cracks. Consider coilover conversion for long-term reliability.

What Owners Are Using

Parts and tips from 211+ owners who fixed this issue

UpgradeAir Suspension Compressor (Arnott #P-3514)
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Typical repair cost:$1,000 - $3,500

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Community Reported

High Confidence211 reportsLast reported by owners Mar 2026Reviewed Mar 2026

On the 2012-2018 Audi S7 4.0T, the Audi S7 (2012-2018) with the heavy 4.0T twin-turbo V8 experiences premature motor mount failure. The hydraulic-filled engine mounts deteriorate and collapse, causing excessive engine movement, vibration, and clunking during acceleration and braking. The 4.0T's high torque output (406+ lb-ft) and the weight of the twin-turbo V8 stress the mounts beyond their design life. Failures commonly occur between 50,000-80,000 miles. Collapsed mounts allow the engine to shift excessively, which can stress exhaust connections, CV axles, and transmission mounts. RS246 and Audizine forums report motor mounts as one of the earlier-failing components on the C7 S6/S7/RS7 platform.

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

Common Symptoms

Noticeable clunk or thud when accelerating from stop
Excessive engine movement visible under hood
Vibration transmitted to cabin at idle
Clunking during hard braking (engine rocks forward)
Exhaust rattle from stressed connections
Transmission shifts feel harsher (engine movement affects alignment)

How to Fix

Replace both engine mounts as a pair ($800-$1,500 for both, $1,500-$2,500 with labor). Always replace BOTH mounts simultaneously—if one has failed, the other is close behind. Use OEM Audi mounts for proper damping characteristics. Aftermarket solid mounts increase NVH (noise/vibration) significantly. INSPECT: Check transmission mount at the same time—it often wears concurrently. Replace transmission mount if showing signs of deterioration ($400-$800 additional).

What Owners Are Using

Parts and tips from 0+ owners who fixed this issue

UpgradeOEM Audi hydraulic engine mounts are the recommended replacement. RS246 forum consensus: aftermarket solid polyurethane mounts are too harsh for daily driving in the S7. (Genuine VW/Audi Engine Mount Set (4.0T))
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TipA simple test: have someone rev the engine in drive with the brake held while you watch under the hood. Excessive engine rocking (more than 1 inch) indicates worn mounts.

Typical repair cost:$1,500 - $2,500

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Medium Confidence0 reportsLast reported by owners Invalid DateReviewed Invalid Date

On the 2012-2018 Audi S7 4.0T, the Audi S7 (2012-2018) with the 4.0T twin-turbo V8 develops carbon buildup on intake valves due to direct fuel injection. With 8 cylinders and twin turbochargers generating high crankcase pressure, carbon accumulation is more aggressive than on smaller engines. The hot-vee design (turbochargers mounted between the cylinder banks) also contributes to higher under-hood temperatures that bake deposits faster. Symptoms appear between 40,000-80,000 miles and include rough idle, misfires, and reduced power. Walnut blasting on a V8 is more expensive than on 4-cylinder engines due to double the cylinders and the complexity of the hot-vee layout. Audizine and AudiWorld forums recommend cleaning every 40,000-60,000 miles as preventive maintenance. Neglecting carbon cleaning can lead to valve damage and $6,000+ engine repairs.

This issue also affects: Buick LeSabre, Buick Park Avenue, Buick Encore

Common Symptoms

Rough or unstable idle, especially when cold
Misfires on one or more cylinders
Hesitation during acceleration
Reduced power output at higher RPM
Poor fuel economy (below 15 MPG city)
Check engine light with misfire codes
Engine stumbling under partial throttle

How to Fix

WALNUT BLASTING: Remove intake manifolds and blast all 8 intake ports with walnut shells ($1,000-$2,000 for V8). The hot-vee design makes this more labor-intensive than typical V8 engines—expect 6-10 hours of labor. Repeat every 40,000-60,000 miles. CATCH CAN: Install dual oil catch cans ($400-$800) to capture PCV vapors from both banks. OIL CHANGES: Use premium 5W-40 synthetic and change every 5,000 miles. DRIVING HABITS: Regular highway driving at higher RPM helps slow carbon accumulation.

What Owners Are Using

Parts and tips from 0+ owners who fixed this issue

TipThe 4.0T hot-vee design makes walnut blasting more complex than typical V8s. Find a shop experienced with Audi 4.0T engines specifically—not all European specialists have done this engine.
UpgradeDual catch can setup required for the 4.0T—one for each bank. 034 Motorsport and JHM offer complete kits designed for the C7 S6/S7 platform. (034 Motorsport Dual Catch Can Kit (4.0T))
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NoteDo not attempt chemical de-carbon solutions on the 4.0T—the hot-vee turbo layout means chemicals can contaminate turbocharger bearings. Walnut blasting is the only safe method.

Typical repair cost:$1,000 - $2,000

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Community Reported

Medium Confidence0 reportsLast reported by owners Invalid DateReviewed Invalid Date

Frequently Asked Questions

What are the most common Audi S7 problems?

According to Au7o's analysis of 468+ owner reports, the 2018-2018 Audi S7 has 4 documented issues. The most frequently reported are: 4.0T Biturbo Coolant Line and Thermostat Failure, Air Suspension Compressor and Strut Failure, Premature Motor Mount Failure (4.0T V8). Of these, 2 are rated critical and should be addressed promptly.

Is the Audi S7 reliable?

The 2018-2018 Audi S7 has 4 known issues documented across 468+ owner reports. 2 issues are rated critical: 4.0T Biturbo Coolant Line and Thermostat Failure and Air Suspension Compressor and Strut Failure. 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 S7 problems?

Repair costs for known Audi S7 issues range from $900 to $3,500, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, 4.0T Biturbo Coolant Line and Thermostat Failure, typically costs $900-$2,800 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.

What is the 2012-2024 Audi S7 4.0T Biturbo Coolant Line and Thermostat Failure?

The S7 shares the 4.0T biturbo V8 cooling system issues with turbo coolant lines cracking under heat cycling. The thermostat housing also cracks, causing slow coolant loss that is hard to detect. Repairs typically run $900-$2,800. Severity: high.

What is the 2012-2024 Audi S7 Air Suspension Compressor and Strut Failure?

The S7 adaptive air suspension system is prone to compressor burnout and strut bladder leaks. The sportback body style adds weight stress on rear struts. Compressor failures are often preceded by strut leaks overworking the pump. Repairs typically run $1,000-$3,500. Severity: high.

What is the 2012-2018 Audi S7 Premature Motor Mount Failure (4.0T V8)?

The Audi S7 (2012-2018) with the heavy 4.0T twin-turbo V8 experiences premature motor mount failure. The hydraulic-filled engine mounts deteriorate and collapse, causing excessive engine movement, vibration, and clunking during acceleration and braking. The 4.0T's high torque out… Repairs typically run $1,500-$2,500. Severity: medium.

What is the 2012-2018 Audi S7 Carbon Buildup on Intake Valves (4.0T Twin-Turbo V8)?

The Audi S7 (2012-2018) with the 4.0T twin-turbo V8 develops carbon buildup on intake valves due to direct fuel injection. With 8 cylinders and twin turbochargers generating high crankcase pressure, carbon accumulation is more aggressive than on smaller engines. The hot-vee desig… Repairs typically run $1,000-$2,000. Severity: medium.

2018 Audi S7 Problems: 4 Issues Every Owner Should Know

All 4 Known Issues

2012-2024 Audi S7: 4.0T Biturbo Coolant Line and Thermostat Failure#

Common Symptoms

How to Fix

What Owners Are Using

Research This Issue

2012-2024 Audi S7: Air Suspension Compressor and Strut Failure#

Common Symptoms

How to Fix

What Owners Are Using

Research This Issue

2012-2018 Audi S7: Premature Motor Mount Failure (4.0T V8)#

Common Symptoms

How to Fix

What Owners Are Using

Research This Issue

2012-2018 Audi S7: Carbon Buildup on Intake Valves (4.0T Twin-Turbo V8)#

Common Symptoms

How to Fix

What Owners Are Using

Research This Issue

Other Audi Models

Frequently Asked Questions

What are the most common Audi S7 problems?

Is the Audi S7 reliable?

How much does it cost to fix common Audi S7 problems?

What is the 2012-2024 Audi S7 4.0T Biturbo Coolant Line and Thermostat Failure?

What is the 2012-2024 Audi S7 Air Suspension Compressor and Strut Failure?

What is the 2012-2018 Audi S7 Premature Motor Mount Failure (4.0T V8)?

What is the 2012-2018 Audi S7 Carbon Buildup on Intake Valves (4.0T Twin-Turbo V8)?