Audi · Known Issues

2018 Audi S8 Problems: 7 Known Issues

2018 model year · 823+ owner reports · Updated September 2026

According to Au7o's analysis of 823+ owner reports, the 2018 Audi S8 has 7 documented known issues, with 4 rated critical. The most serious are Adaptive Air Suspension Multi-Point Failure ($1,200-$4,500 repair), ZF 8-Speed Torque Converter and Valve Body Issues ($2,500-$6,000 repair), 4.0T Turbo Coolant System Degradation ($1,000-$3,500 repair) and Water-to-Air Intercooler Internal Coolant Leak (Coolant into Intake) ($1,500-$3,500 repair). The most commonly reported issue is Adaptive Air Suspension Multi-Point Failure with 292 owner reports. Across all issues with published estimates, repair costs range from $200 to $6,000. DIY maintenance guides at au7o.io.

Frequently Asked Questions

What are the most common Audi S8 problems?

According to Au7o's analysis of 823+ owner reports, the 2018 Audi S8 has 7 documented issues. The most frequently reported are: Adaptive Air Suspension Multi-Point Failure, ZF 8-Speed Torque Converter and Valve Body Issues, 4.0T Turbo Coolant System Degradation. Of these, 4 are rated critical and should be addressed promptly.

Is the Audi S8 reliable?

The 2018 Audi S8 has 7 known issues documented across 823+ owner reports. 4 issues are rated critical: Adaptive Air Suspension Multi-Point Failure and ZF 8-Speed Torque Converter and Valve Body Issues and 4.0T Turbo Coolant System Degradation and Water-to-Air Intercooler Internal Coolant Leak (Coolant into Intake). 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 S8 problems?

Repair costs for known Audi S8 issues range from $200 to $6,000, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, Adaptive Air Suspension Multi-Point Failure, typically costs $1,200-$4,500 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.

What is the 2013-2024 Audi S8 Adaptive Air Suspension Multi-Point Failure?

The S8 full-size luxury sedan places extreme demands on the air suspension system. All four struts and the compressor commonly need replacement between 60,000-100,000 miles. The heavy curb weight accelerates bladder wear. Repairs typically run $1,200-$4,500. Severity: high.

What is the 2013-2024 Audi S8 ZF 8-Speed Torque Converter and Valve Body Issues?

The S8 high-torque application stresses the ZF 8HP torque converter and valve body. Shudder, delayed shifts, and harsh engagement develop as the converter clutch wears and valve body solenoids degrade. Repairs typically run $2,500-$6,000. Severity: high.

What is the 2013-2024 Audi S8 4.0T Turbo Coolant System Degradation?

The S8 4.0T V8 shares coolant line issues with other 4.0T Audi models but the heavier sedan and higher power tune accelerate wear. Turbo oil and coolant line failures can cause expensive damage if not caught early. Repairs typically run $1,000-$3,500. Severity: high.

What is the 2013-2018 Audi S8 Water-to-Air Intercooler Internal Coolant Leak (Coolant into Intake)?

The 4.0T uses a compact water-to-air charge-air cooler mounted in the hot 'V' between the cylinder banks. The intercooler core can develop an internal leak that allows engine coolant to weep directly into the pressurized intake path. Owners report slow, unexplained coolant loss w… Repairs typically run $1,500-$3,500. Severity: high.

What is the 2013-2018 Audi S8 Direct-Injection Carbon Buildup on Intake Valves (Misfires / Rough Idle)?

Like other VAG direct-injection engines, the 4.0T runs port-bypassing direct injection, so no fuel washes the back of the intake valves. Carbon deposits accumulate on the valves and ports over time, restricting airflow and degrading the seal. Owners report a gradual power loss, r… Repairs typically run $600-$1,400. Severity: medium.

What is the 2007-2018 Audi S8 Clogged Sunroof / Plenum Drains Causing Water Intrusion and Electronics Damage?

Like other large Audi sedans, the S8 relies on sunroof drain channels and cowl/plenum drains to route rainwater away from the cabin and the electronics housed in the plenum area. The plastic drain connectors and channels become brittle and crack, and the plenum drains clog with d… Repairs typically run $200-$3,500. Severity: medium.

What is the 2013-2018 Audi S8 2013-2018 S8 Warm-Soak Long-Crank or No-Start - Fuel Diagnosis Required?

Audi TSB 2046724/5 covers sporadic warm-engine no-start or long cranking after the vehicle sits without fully cooling. A rich-mixture DTC may occur, but often there is no DTC. Audi’s procedure distinguishes fuel in the oil from a short-trip profile, ECM software, high-pressure in… Severity: medium.

All 7 Known Issues

When Issues Typically Appear

2013-2024 Audi S8: 4.0T Turbo Coolant System Degradation#

2013-2018 Audi S8: Water-to-Air Intercooler Internal Coolant Leak (Coolant into Intake)#

2013-2024 Audi S8: Adaptive Air Suspension Multi-Point Failure#

2013-2024 Audi S8: ZF 8-Speed Torque Converter and Valve Body Issues#

2013-2018 Audi S8: Direct-Injection Carbon Buildup on Intake Valves (Misfires / Rough Idle)#

2007-2018 Audi S8: Clogged Sunroof / Plenum Drains Causing Water Intrusion and Electronics Damage#

2013-2018 Audi S8: 2013-2018 S8 Warm-Soak Long-Crank or No-Start - Fuel Diagnosis Required#

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