2008-2025 Audi S5 Problems: 6 Issues Every Owner Should Know

2008-2025 model years · 497+ owner reports · Updated May 2026

According to Au7o's analysis of 497+ owner reports, the 2008-2025 Audi S5 has 6 documented known issues, with 2 rated critical. The most serious are EA839 Water Pump Internal Leak and Vacuum System Contamination (2.9T) ($1,200-$3,500 repair) and Crankshaft Pulley (Harmonic Balancer) Failure (3.0T) ($800-$5,000 repair). The most commonly reported issue is Thermostat and Water Pump Assembly Failure with 211 owner reports. Across all issues, repair costs range from $300 to $5,000. DIY maintenance guides at au7o.io.

All 6 Known Issues

When Issues Typically Appear

PCV Valve (Crankcase Vent Valve) Failure (3.0T)

30K-100K

EA839 Water Pump Internal Leak and Vacuum System Contamination (2.9T)

40K-70K

Direct Injection Carbon Buildup

40K-60K

Crankshaft Pulley (Harmonic Balancer) Failure (3.0T)

60K-100K

Thermostat and Water Pump Assembly Failure

60K-80K

025K50K75K100K mi

On the 2018-2024 Audi S5, the B9/B9.5 Audi S5 (2018-2024) with the EA839 2.9T twin-turbo V6 suffers from a particularly insidious water pump failure. Unlike typical water pumps that leak externally, the EA839 water pump leaks INTERNALLY. The pump uses vacuum to operate a slide valve controlling impeller actuation. When the internal seals fail, coolant is drawn into the vacuum system and migrates into other components where coolant should never be present—including the brake booster, turbo wastegate actuators, and other vacuum-operated systems. This makes the failure especially dangerous as it can affect braking and boost control simultaneously. New German Performance and AudiWorld forums describe this as a 'when, not if' failure on EA839 engines. Failures typically occur between 40,000-70,000 miles.

This issue also affects: Audi A4 allroad, Audi Q5, Audi Q7

Common Symptoms

Coolant level dropping with no visible external leak
Sweet coolant smell but no puddle under car
Brake pedal feels soft or spongy (coolant in brake booster)
Turbo boost irregularities (coolant in wastegate actuator vacuum lines)
Check engine light with coolant temperature or boost codes
White residue in vacuum lines when inspected
Engine overheating warning

How to Fix

Replace water pump assembly with UPDATED revision ($1,200-$2,500 installed). The EA839 water pump replacement requires significant disassembly—5-8 hours of labor. CRITICAL: Inspect ALL vacuum lines, brake booster, and wastegate actuators for coolant contamination. If coolant entered the brake booster, replace it immediately ($800-$1,500)—this is a SAFETY issue. Flush the vacuum system thoroughly. Use OEM replacement pump with updated seals. PREVENTION: Monitor coolant level monthly. If coolant drops with no visible leak, suspect internal water pump failure immediately.

What Owners Are Using

Parts and tips from 0+ owners who fixed this issue

UpgradeOEM EA839 water pump with updated internal seals. Check for latest revision number from your Audi parts counter. Earlier revisions are more failure-prone. (Genuine VW/Audi EA839 Water Pump Assembly (Updated))
View on Amazon
NoteThis is NOT a typical water pump leak. Coolant enters the vacuum system and can contaminate your brake booster. If you notice a soft brake pedal AND dropping coolant, get this inspected IMMEDIATELY—it is a safety issue.
TipWhen replacing the water pump, have the shop inspect all vacuum lines for white coolant residue. Any contaminated lines or actuators must be replaced or flushed.

Typical repair cost:$1,200 - $3,500

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Community Reported

Medium Confidence0 reportsLast reported by owners Invalid DateReviewed Invalid Date

On the 2010-2017 Audi S5 3.0T, the Audi S5 (2010-2017) with the 3.0T supercharged V6 is prone to crankshaft pulley (harmonic balancer) failure. The rubber damper between the inner and outer sections of the pulley delaminates and separates, causing dangerous pulley wobble. When the pulley fails, the serpentine belt shreds, disabling the supercharger (complete loss of boost), power steering, alternator, and A/C compressor. At highway speed, this means sudden loss of power steering and supercharger boost—a safety hazard. Audi revised the part from revision E to F, acknowledging the design flaw. Audizine and A5OC forums document numerous failures between 60,000-100,000 miles. Early models (2010-2013) are most affected. If the separated pulley damages the crankshaft timing, repair costs can exceed $5,000.

This issue also affects: Audi A5, Audi A6 allroad, Audi A7

Common Symptoms

Visible pulley wobble when engine is running
Serpentine belt shredding or squealing
Sudden loss of supercharger boost (car feels like a V6)
Power steering failure (heavy steering)
Battery light illuminated (alternator not charging)
A/C stops working
Unusual vibration from front of engine
Drivetrain vibration that feels like transmission issue

How to Fix

Replace crankshaft pulley/harmonic balancer with LATEST REVISION (revision F or later) part ($300-$600 for part, $800-$1,700 with labor). This is NOT a DIY-friendly repair—requires specialized holding tools and precise torque. If belts are damaged, replace serpentine belt and tensioner ($200-$400 additional). INSPECT: Check for collateral damage to supercharger snout, idler pulleys, and timing. If timing was affected, expect $3,000-$5,000 additional repair. PREVENTIVE: Inspect pulley for wobble at every oil change. Consider preemptive replacement at 80,000 miles on 2010-2013 models.

What Owners Are Using

Parts and tips from 0+ owners who fixed this issue

UpgradeOEM crankshaft pulley latest revision 06E105251F (revision F). Ensure you get the LATEST revision—earlier revisions A-E have higher failure rates. All 3.0T motors (S4, S5, Q5, SQ5, A6, A7) use the same part. (Genuine VW/Audi #06E105251F)
View on Amazon
NoteIf you notice the serpentine belt suddenly shredding or hear unusual vibration from the engine, STOP DRIVING immediately. Continued operation with a failed pulley can damage the crankshaft and supercharger.
TipA simple visual check at each oil change can catch this before catastrophic failure. Look for any visible gap or wobble between the inner hub and outer ring of the crank pulley while the engine is running.

Typical repair cost:$800 - $5,000

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Community Reported

Medium Confidence0 reportsLast reported by owners Invalid DateReviewed Invalid Date

Community Reported

184 owners

On the 2008-2025 Audi S5 3.0T, the water-to-air intercooler system on the S5 3.0T uses an electric coolant pump that can fail, causing elevated charge air temperatures and reduced power. Heat soak becomes severe in warm climates.

This issue also affects: Audi A3, Audi A5, Audi A6

Common Symptoms

Heat soak power loss
Reduced boost performance
Intercooler pump fault code
Elevated intake temps
Sluggish acceleration in heat
Check engine light

How to Fix

Replace intercooler coolant pump. Check intercooler lines for leaks and flush the circuit during replacement.

What Owners Are Using

Parts and tips from 184+ owners who fixed this issue

UpgradeIntercooler Coolant Pump (Pierburg #7.02078.37.0)
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Typical repair cost:$300 - $700

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Community Reported

High Confidence184 reportsLast reported by owners Mar 2026Reviewed Mar 2026

Community Reported

102 owners

On the 2008-2025 Audi S5, the S5 suffers from carbon deposit accumulation on intake valves common to all Audi direct-injected engines. The performance-oriented tuning makes power loss from carbon more noticeable than in base models.

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

Common Symptoms

Rough idle
Power loss
Cold start misfires
Hesitation under load
Check engine light
Poor throttle response

How to Fix

Walnut blast intake valves every 40,000-60,000 miles. Install oil catch can to reduce oil vapor reaching valves.

What Owners Are Using

Parts and tips from 102+ owners who fixed this issue

UpgradeOil Catch Can Kit (034Motorsport #034-101-1000)
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Typical repair cost:$400 - $900

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Community Reported

High Confidence102 reportsLast reported by owners Mar 2026Reviewed Mar 2026

On the 2010-2017 Audi S5 3.0T, the Audi S5 (2010-2017) with the 3.0T supercharged V6 has a chronic PCV valve (also called air-oil separator or crankcase vent valve) failure. The PCV valve diaphragm degrades over time, causing oil leaks, check engine lights, rough idle, and a loud squealing/whistling noise from the engine. The 3.0T PCV is located at the rear of the engine near the firewall, making it moderately difficult to access. Many B8/B8.5 S5 owners replace the PCV valve and water pump simultaneously to save on future labor costs, since both are common failure items. Audizine, ShopDAP, and Motor Werke report PCV failure as a near-certainty before 100,000 miles. The repair is moderate in cost but ignoring it leads to vacuum leaks and accelerated oil consumption.

This issue also affects: Buick LeSabre, Buick Park Avenue, Jeep Grand Wagoneer

Common Symptoms

Loud squealing or whistling noise from engine bay
Oil leaks around valve covers or PCV housing
Check engine light with lean mixture codes (P0171, P0174)
Rough or unstable idle
Excessive oil consumption (more than 1 qt per 3,000 miles)
Oil residue around PCV valve area
Vacuum leak symptoms (surging idle, poor throttle response)

How to Fix

Replace PCV valve/crankcase vent valve ($200-$500 for part, $600-$1,200 with labor). The PCV is located at the rear of the 3.0T engine near the firewall—labor is 2-4 hours depending on shop access method. RECOMMENDED: Replace water pump and thermostat at the same time (both require partial engine disassembly to access). Use OEM or Dorman replacement. PREVENTION: Change oil every 5,000 miles with high-quality synthetic. Avoid extended oil change intervals which accelerate PCV diaphragm degradation.

What Owners Are Using

Parts and tips from 0+ owners who fixed this issue

UpgradeOEM PCV valve 06E103547E for B8/B8.5 3.0T. Dorman 911-348 is a quality aftermarket alternative. Avoid cheap eBay replacements. (Genuine VW/Audi #06E103547E)
View on Amazon
TipIf you're replacing the PCV, also replace the water pump and thermostat at the same time. Both are known failure items on the 3.0T and share labor overlap—saves $500+ in future labor costs.
NoteA failed PCV valve creates a vacuum leak that causes lean running conditions. Prolonged driving with a failed PCV can damage catalytic converters and increase oil consumption.

Typical repair cost:$600 - $1,200

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Community Reported

Medium Confidence0 reportsLast reported by owners Invalid DateReviewed Invalid Date

Community Reported

211 owners

On the 2008-2025 Audi S5 3.0T, the S5 3.0T thermostat and water pump assembly uses a plastic housing that degrades over time. Leaks develop at the housing seams and O-ring seals, often around 60,000-80,000 miles.

This issue also affects: Audi A5, Audi A6 allroad, Audi A7

Common Symptoms

Coolant leak at rear of engine
Overheating
Low coolant warning
Temperature gauge spikes
Sweet coolant smell
Steam from engine bay

How to Fix

Replace thermostat/water pump assembly. Upgrade to revised housing if available.

What Owners Are Using

Parts and tips from 211+ owners who fixed this issue

UpgradeWater Pump and Thermostat Kit (Graf #PA1273)
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Typical repair cost:$400 - $1,000

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211+ owners have reported this issue

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Community Reported

High Confidence211 reportsLast reported by owners Mar 2026Reviewed Mar 2026

Frequently Asked Questions

What are the most common Audi S5 problems?

According to Au7o's analysis of 497+ owner reports, the 2008-2025 Audi S5 has 6 documented issues. The most frequently reported are: EA839 Water Pump Internal Leak and Vacuum System Contamination (2.9T), Crankshaft Pulley (Harmonic Balancer) Failure (3.0T), Thermostat and Water Pump Assembly Failure. Of these, 2 are rated critical and should be addressed promptly.

Is the Audi S5 reliable?

The 2008-2025 Audi S5 has 6 known issues documented across 497+ owner reports. 2 issues are rated critical: EA839 Water Pump Internal Leak and Vacuum System Contamination (2.9T) and Crankshaft Pulley (Harmonic Balancer) Failure (3.0T). 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 S5 problems?

Repair costs for known Audi S5 issues range from $300 to $5,000, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, EA839 Water Pump Internal Leak and Vacuum System Contamination (2.9T), typically costs $1,200-$3,500 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.

What year Audi S5 is the most reliable?

Reliability varies across model years of the Audi S5. Based on documented issues, problems are most commonly reported in earlier model years. Au7o recommends checking the specific known issues for your target year before purchasing, and having a pre-purchase inspection performed by a qualified mechanic. Our known issues database covers the 2008-2025 Audi S5 with 6 documented issues documented across 497+ owner reports.

What is the 2018-2024 Audi S5 EA839 Water Pump Internal Leak and Vacuum System Contamination (2.9T)?

The B9/B9.5 Audi S5 (2018-2024) with the EA839 2.9T twin-turbo V6 suffers from a particularly insidious water pump failure. Unlike typical water pumps that leak externally, the EA839 water pump leaks INTERNALLY. The pump uses vacuum to operate a slide valve controlling impeller a… Repairs typically run $1,200-$3,500. Severity: high.

What is the 2010-2017 Audi S5 Crankshaft Pulley (Harmonic Balancer) Failure (3.0T)?

The Audi S5 (2010-2017) with the 3.0T supercharged V6 is prone to crankshaft pulley (harmonic balancer) failure. The rubber damper between the inner and outer sections of the pulley delaminates and separates, causing dangerous pulley wobble. When the pulley fails, the serpentine… Repairs typically run $800-$5,000. Severity: high.

What is the 2008-2025 Audi S5 Thermostat and Water Pump Assembly Failure?

The S5 3.0T thermostat and water pump assembly uses a plastic housing that degrades over time. Leaks develop at the housing seams and O-ring seals, often around 60,000-80,000 miles. Repairs typically run $400-$1,000. Severity: medium.

What is the 2008-2025 Audi S5 3.0T Supercharger Intercooler Pump Failure?

The water-to-air intercooler system on the S5 3.0T uses an electric coolant pump that can fail, causing elevated charge air temperatures and reduced power. Heat soak becomes severe in warm climates. Repairs typically run $300-$700. Severity: medium.

What is the 2008-2025 Audi S5 Direct Injection Carbon Buildup?

The S5 suffers from carbon deposit accumulation on intake valves common to all Audi direct-injected engines. The performance-oriented tuning makes power loss from carbon more noticeable than in base models. Repairs typically run $400-$900. Severity: medium.

What is the 2010-2017 Audi S5 PCV Valve (Crankcase Vent Valve) Failure (3.0T)?

The Audi S5 (2010-2017) with the 3.0T supercharged V6 has a chronic PCV valve (also called air-oil separator or crankcase vent valve) failure. The PCV valve diaphragm degrades over time, causing oil leaks, check engine lights, rough idle, and a loud squealing/whistling noise from… Repairs typically run $600-$1,200. Severity: medium.

All 6 Known Issues

When Issues Typically Appear

2018-2024 Audi S5: EA839 Water Pump Internal Leak and Vacuum System Contamination (2.9T)#

Common Symptoms

How to Fix

What Owners Are Using

Research This Issue

2010-2017 Audi S5: Crankshaft Pulley (Harmonic Balancer) Failure (3.0T)#

Common Symptoms

How to Fix

What Owners Are Using

Research This Issue

2008-2025 Audi S5: 3.0T Supercharger Intercooler Pump Failure#

Common Symptoms

How to Fix

What Owners Are Using

Research This Issue

2008-2025 Audi S5: Direct Injection Carbon Buildup#

Common Symptoms

How to Fix

What Owners Are Using

Research This Issue

2010-2017 Audi S5: PCV Valve (Crankcase Vent Valve) Failure (3.0T)#

Common Symptoms

How to Fix

What Owners Are Using

Research This Issue

2008-2025 Audi S5: Thermostat and Water Pump Assembly Failure#

Common Symptoms

How to Fix

What Owners Are Using

Research This Issue

Other Audi Models

Frequently Asked Questions

What are the most common Audi S5 problems?

Is the Audi S5 reliable?

How much does it cost to fix common Audi S5 problems?

What year Audi S5 is the most reliable?

What is the 2018-2024 Audi S5 EA839 Water Pump Internal Leak and Vacuum System Contamination (2.9T)?

What is the 2010-2017 Audi S5 Crankshaft Pulley (Harmonic Balancer) Failure (3.0T)?

What is the 2008-2025 Audi S5 Thermostat and Water Pump Assembly Failure?

What is the 2008-2025 Audi S5 3.0T Supercharger Intercooler Pump Failure?

What is the 2008-2025 Audi S5 Direct Injection Carbon Buildup?

What is the 2010-2017 Audi S5 PCV Valve (Crankcase Vent Valve) Failure (3.0T)?