The 2010 S5 with the 4.2L V8 is a phenomenal performer hampered by catastrophic oil consumption issues stemming from defective piston rings—expect major engine work between 60k-100k miles. Otherwise solid chassis and transmission, but that engine problem shadows everything.
Excessive Oil Consumption / Piston Ring Failure
Common · high severity
Typical onset: 60,000-100,000 mi
Symptoms: Blue smoke on cold start or hard acceleration, Burning through 1+ quart every 500-1000 miles, Carbon buildup on intake valves causing rough idle, Check engine light for misfires, Fouled spark plugs
Fix: Factory defect in piston ring design allows oil past into combustion chambers. Temporary fix is valve cleaning and top-end service (8-12 hours), but real solution requires engine-out piston ring replacement or short block swap (25-35 hours). Some opt for full engine rebuild addressing bearings simultaneously.
Estimated cost: $8,000-15,000
Carbon Buildup on Intake Valves (Direct Injection)
Common · medium severity
Typical onset: 50,000-80,000 mi
Symptoms: Rough idle especially when cold, Hesitation or stumble on acceleration, Reduced fuel economy, Long crank times, Misfires under load
Fix: Direct injection means no fuel washing valves clean—carbon accumulates. Walnut blasting required every 50-60k miles (6-8 hours labor). If combined with oil consumption problem, carbon builds faster and more severely.
Estimated cost: $600-1,200
Transmission Oil Cooler Lines Leaking
Occasional · medium severity
Typical onset: 80,000-120,000 mi
Symptoms: Trans fluid puddles under car, Low fluid warnings on dash, Harsh or delayed shifts when fluid runs low, Pink or red fluid near front of engine bay
Fix: Metal lines or rubber connections at cooler corrode and crack. Requires replacing lines and possibly cooler itself, plus fluid flush (3-5 hours). Catch early before transmission damage occurs.
Estimated cost: $800-1,500
Transmission Mount Failure
Occasional · low severity
Typical onset: 70,000-110,000 mi
Symptoms: Clunk when shifting from Park to Drive/Reverse, Excessive vibration at idle in gear, Harsh engagement during shifts, Visible sagging or torn rubber on mount
Fix: The S-tronic or automatic trans mount wears from the torque of the V8. Replacement is straightforward (2-3 hours), but requires supporting transmission properly.
Estimated cost: $400-700
Timing Chain Tensioner and Guide Wear
Occasional · high severity
Typical onset: 100,000-150,000 mi
Symptoms: Rattling noise on cold start for first 5-10 seconds, Metallic ticking from front of engine, Check engine codes for cam/crank correlation, Loss of power if chain skips
Fix: Early tensioners and guides can wear, allowing chain slap. If caught early, tensioners/guides replacement takes 12-16 hours. If chain jumps timing, valve damage likely—becomes full head or engine job.
Estimated cost: $2,500-4,000
Supercharger Belt Tensioner (if equipped)
Rare · medium severity
Symptoms: Squealing on startup or under load, Loss of power, Visible belt wobble or cracking
Fix: Note: 2010 S5 4.2L is naturally aspirated, but if confused with supercharged 3.0T models, tensioner is common wear item. Not applicable to this engine.
PCV System and Valve Cover Breather Failures
Occasional · low severity
Typical onset: 60,000-100,000 mi
Symptoms: Oil leaks from valve covers, Whistle or hissing from engine bay, Check engine light for lean/rich codes, Oil mist in intake tubing
Fix: Rubber diaphragms in PCV valves and breather system harden and crack. Requires valve cover removal and replacement of internal breathers and hoses (4-6 hours). Often done during carbon cleaning.
Estimated cost: $800-1,400
Owner tips
Budget $1,000/year minimum for the inevitable oil consumption and carbon cleaning—check oil every fillup once past 60k miles
If buying used, demand oil consumption test over 1,000 miles and compression/leak-down test—walk away if burning more than 1qt per 1,500 miles
Use only Audi-approved 5W-40 synthetic and OEM spark plugs—cheaper stuff accelerates carbon and ring wear
Extended Audi warranty covered some ring jobs under settlement—verify if prior owner claimed it before buying
Buy only if engine has already been rebuilt with updated rings or you have $10k set aside for the inevitable—otherwise, spectacular car hiding a ticking time bomb.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.
Fitment notes: AGM battery required; located in trunk under floor panel
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Every control module on the 2008-2016 Audi S5 — where it lives, replacement time, and what it takes to program a replacement. Modules marked dealer / factory tool won't work after a part swap alone — budget for programming.
📍 Rear trunk lid, integrated in trunk handle or license plate area
🔧 VCDS or Autel
⚠️ Optional equipment. Calibration for parking guidelines may be needed.
Aftermarket tool coverage varies by software version and vehicle build — treat "aftermarket tool" rows as "usually possible" and verify against your tool maker's coverage list before promising a customer. Spot a wrong location or hour? Tell us — corrections ship fast here.
Size-standard part numbers — verify your connector type before buying. Rear blades are model-specific; check the package's vehicle list.
Fuel economy figures are EPA data via fueleconomy.gov (median across matching trims). Performance figures are compiled estimates for the 2010 Audi S5 4.2L V8 and can vary by trim.
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Lexus & Toyota Mechanic · 20+ years.