The 2016 S63 AMG with the M157 5.5L BiTurbo is a high-performance flagship with exceptional power, but the engine suffers from a catastrophic design flaw: inadequate oiling at cylinder 8 leads to bore scoring and eventual total engine failure, often requiring complete rebuilds or replacement.
M157 Cylinder 8 Bore Scoring and Engine Failure
Common · high severity
Typical onset: 40,000-80,000 mi
Symptoms: Cold-start engine knock or rattle from passenger-side rear cylinder, Metal flakes or glitter in oil during changes, Increased oil consumption (more than 1 qt per 1,000 mi), Check engine light with misfire codes (P0308 cylinder 8), Loss of power and rough idle as damage progresses
Fix: Complete engine rebuild or short block replacement required. This involves removing the engine, disassembling to bare block, honing or sleeving cylinders (especially 8), new pistons, rings, bearings, gaskets, and reassembly. Expect 40-60 hours labor minimum. Many shops recommend short block replacement to avoid machining costs. This is a known M157 defect affecting thousands of units.
Estimated cost: $18,000-35,000
Twin Turbocharger Failure
Occasional · high severity
Typical onset: 60,000-100,000 mi
Symptoms: Loud whistling or whining under boost, Blue smoke from exhaust on acceleration, Significant loss of power, Underboost or overboost codes (P0299, P0234), Oil leaking from turbo inlet or outlet connections
Fix: Turbocharger replacement requires dropping exhaust, removing heat shields, and dealing with seized studs. Each turbo runs 8-12 hours labor due to tight engine bay. Often both turbos replaced together if one fails due to similar wear. Oil feed line inspection critical to prevent repeat failure.
Estimated cost: $4,500-8,000 per turbo
7-Speed MCT Transmission Oil Cooler Leaks
Common · medium severity
Typical onset: 50,000-90,000 mi
Symptoms: Transmission fluid puddles under vehicle center, Low transmission fluid warnings on dash, Burnt transmission fluid smell, Harsh or delayed shifting when fluid is low, Pink or red fluid visible on cooler lines or radiator area
Fix: Replace transmission oil cooler and associated lines. Cooler is mounted low and takes road debris damage. Requires dropping undertray, draining and refilling transmission (9 quarts). 3-5 hours labor. Always replace O-rings and seals during cooler swap.
Estimated cost: $1,200-2,200
Transmission Mounts Collapsing
Common · medium severity
Typical onset: 60,000-100,000 mi
Symptoms: Clunk or thud when shifting from Park to Drive or Reverse, Vibration through cabin at idle in gear, Excessive driveline movement visible during throttle blip, Transmission seems to 'drop' into gear harshly
Fix: Replace transmission mounts (typically driver side fails first, but replace both). Requires supporting transmission, removing mount bolts, and R&R. 2-3 hours labor. Hydraulic mounts fail from age and heat cycling in high-torque applications.
Estimated cost: $800-1,400
Airmatic Suspension Strut Leaks
Occasional · medium severity
Typical onset: 70,000-110,000 mi
Symptoms: Vehicle sits low on one corner after overnight parking, Suspension warning light and 'Visit Workshop' message, Audible compressor running excessively, Visible oil residue on strut body, Rough ride quality before compressor catches up
Fix: Replace failed air strut assembly. Front struts are 2-3 hours each, rears 1.5-2 hours. Requires disabling Airmatic system, supporting vehicle, and calibrating ride height after installation. Compressor may also need replacement if overworked from leaking strut (add $1,500-2,000).
Estimated cost: $1,800-2,800 per strut
ABC (Active Body Control) Pump and Accumulator Failure
Occasional · high severity
Typical onset: 80,000-120,000 mi
Symptoms: ABC warning light with 'Stop Vehicle Leave Engine Running' message, Vehicle dropping to bump stops, Groaning or whining noise from ABC pump, ABC fluid leaks visible under front of vehicle, Loss of adaptive suspension function
Fix: ABC pump or pulsation damper replacement. Pump is in front subframe area, requires fluid evacuation, hose removal, and bleeding system after install. 6-8 hours labor. System uses special ABC fluid, not standard hydraulic fluid. Accumulator (pulsation damper) often replaced preventively with pump.
Estimated cost: $3,500-6,000
Fuel Injector and High-Pressure Fuel Pump Issues
Occasional · medium severity
Typical onset: 60,000-100,000 mi
Symptoms: Rough idle or misfires at cold start, Hesitation or stumble during acceleration, Fuel smell in cabin or engine bay, Check engine light with fuel trim or injector codes, Hard starting after sitting
Fix: Direct injection systems run high pressure and injectors carbon up or fail electrically. Individual injector replacement is 1-2 hours labor each due to intake plenum access. High-pressure pump (on cylinder head) is 4-5 hours. Decarbonization service often needed alongside injector work.
Estimated cost: $800-1,500 per injector, $2,000-3,000 for HP pump
Owner tips
CRITICAL: Do pre-purchase borescope inspection of cylinder 8 — bore scoring is a ticking time bomb on M157 engines
Use only Mercedes-approved 0W-40 oil and change every 5,000 miles maximum to slow (not prevent) bore wear
Keep transmission fluid changes on 40,000-mile intervals — MCT transmission is sensitive to degraded fluid
Budget $3,000-5,000 annually for maintenance and repairs after 60,000 miles
Extended warranty is nearly mandatory if buying used — engine replacement alone exceeds most car's value
Only buy if you can afford a $25,000 engine rebuild or find a confirmed low-mileage example with documented cylinder 8 inspection — otherwise this is a financial hand grenade.
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 engine compartment; auxiliary battery in trunk
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Every control module on the 2014-2017 Mercedes-Benz S63 AMG — 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.
Parktronic Control Unit (PTS)0.7 hr R&Raftermarket tool +0.3 hr▸ programming details
📍 Trunk, right side panel
🔧 Xentry/DAS or Autel
⚠️ Sensor calibration required after replacement.
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 2016 Mercedes-Benz S63 AMG 5.5L V8 BiTurbo M157 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.