Audi S5 Problems: 5 Issues Every Owner Should Know
2010-2026 model years · Based on 0+ owner reports · Last updated March 2026
According to Au7o's analysis of 0+ owner reports, the 2010-2026 Audi S5 has 5 documented known issues, with 2 rated critical by the Au7o research team. The most serious are Crankshaft Pulley (Harmonic Balancer) Failure (3.0T) ($800-$5,000 repair) and EA839 Water Pump Internal Leak and Vacuum System Contamination (2.9T) ($1,200-$3,500 repair). Across all issues, repair costs range from $600 to $5,000. Full technical analysis and DIY maintenance guides at au7o.io.
All 5 Known Issues
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.
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)
- 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.
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.
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))
- 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.
The 2.9L twin-turbo V6 uses direct injection exclusively, which means no fuel washes over the intake valves to clean them. Carbon deposits accumulate on intake valves, reducing airflow and causing misfires and rough running.
Common Symptoms
- Rough idle
- Reduced power
- Misfires
- Hesitation on acceleration
How to Fix
The Audi RS5 B8 with the naturally aspirated 4.2L V8 develops significant carbon buildup on the intake valves due to direct injection. The high-revving nature of this engine makes carbon buildup particularly impactful on performance.
Common Symptoms
- Power loss from original spec
- Rough idle
- Misfires
- Hesitation at lower RPMs
- Reduced throttle response
How to Fix
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.
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)
- 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.
Frequently Asked Questions
What are the most common Audi S5 problems?
According to Au7o's analysis of 0+ owner reports, the 2010-2026 Audi S5 has 5 documented issues. The most frequently reported are: Crankshaft Pulley (Harmonic Balancer) Failure (3.0T), EA839 Water Pump Internal Leak and Vacuum System Contamination (2.9T), Direct Injection Carbon Buildup on Intake Valves. Of these, 2 are rated critical and should be addressed promptly.
Is the Audi S5 reliable?
The 2010-2026 Audi S5 has 5 known issues documented across 0+ owner reports. 2 issues are rated critical: Crankshaft Pulley (Harmonic Balancer) Failure (3.0T) and EA839 Water Pump Internal Leak and Vacuum System Contamination (2.9T). 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 $600 to $5,000, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, Crankshaft Pulley (Harmonic Balancer) Failure (3.0T), typically costs $800-$5,000 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 owner reports, issues 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 2010-2026 Audi S5 with 5 documented issues from 0+ owner reports.
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