The 2014 S63 AMG with the M157 5.5L twin-turbo V8 is a performance flagship that suffers from catastrophic engine failures due to a specific crankshaft/bearing design flaw, plus typical 7-speed transmission weak points. When they run, they're exceptional; when they fail, it's often a complete engine replacement scenario.
M157 Engine Balance Shaft/Main Bearing Failure
Common · high severity
Typical onset: 40,000-80,000 mi
Symptoms: Sudden catastrophic engine knock or rattle at startup or idle, Metal shavings in oil during routine change, Check engine light with bearing-related codes, Complete loss of oil pressure, Engine seizure in worst cases
Fix: The M157's balance shaft module and main bearings have a known defect causing premature wear and catastrophic failure. Mercedes issued a service campaign but many engines failed outside warranty. Requires complete engine disassembly at minimum; most cases end up being short block or complete engine replacement. 40-60 labor hours for short block, 50-70+ for long block.
Estimated cost: $25,000-45,000
722.9 Transmission Oil Cooler Line Leaks
Common · medium severity
Typical onset: 60,000-100,000 mi
Symptoms: Transmission fluid spots under vehicle, Burnt transmission smell, Harsh or delayed shifts when fluid is low, Transmission temperature warning on dash
Fix: The cooler lines running to the heat exchanger corrode and develop leaks, especially where they connect at crimped fittings. Requires replacing lines and topping off ATF. Sometimes the entire cooler assembly needs replacement if internal contamination occurred. 3-5 hours labor depending on access.
Estimated cost: $800-1,800
Transmission Mounts Collapse
Common · medium severity
Typical onset: 50,000-90,000 mi
Symptoms: Clunk when shifting from Park to Drive or Reverse, Excessive vibration at idle in gear, Drivetrain shudder during aggressive acceleration, Visible sagging of transmission when inspected on lift
Fix: The hydraulic transmission mounts wear out and collapse, especially with aggressive driving typical of AMG ownership. Both engine and transmission mounts should be replaced as a set for best results. 4-6 hours labor with proper support equipment.
Estimated cost: $1,200-2,200
Turbocharger Wastegate Rattle and Actuator Failure
Occasional · medium severity
Typical onset: 70,000-120,000 mi
Symptoms: Rattle from engine bay on cold start that disappears when warm, Reduced boost pressure and power loss, Check engine light with underboost/overboost codes P0234/P0299, Turbo whistle or unusual spool sounds
Fix: The wastegate actuators stick or fail, and the wastegate flapper arms develop play causing rattle. Sometimes cleaned and freed up, but usually requires turbocharger replacement or rebuild. Each turbo is 8-12 hours labor due to tight engine bay. If one fails, consider doing both.
Estimated cost: $3,500-6,500 per side
Airmatic Suspension Compressor and Strut Leaks
Occasional · medium severity
Typical onset: 60,000-110,000 mi
Symptoms: Vehicle sits low after sitting overnight, Airmatic warning on dash, Compressor runs constantly or excessively, Uneven ride height side-to-side, Clunking over bumps from worn strut mounts
Fix: The air struts develop leaks at seals, and the compressor works overtime then fails. Valve block can also leak internally. Strut replacement is 2-3 hours each corner; compressor is 3-4 hours. Diagnose carefully—could be multiple components. Many owners convert to coilovers to eliminate the system entirely.
Estimated cost: $1,800-3,500 per strut, $2,500-3,500 for compressor
ABC Active Body Control Hydraulic Leaks (if equipped)
Occasional · high severity
Typical onset: 70,000-100,000 mi
Symptoms: ABC warning light with vehicle lowered to ground, Hydraulic fluid puddles under car (green fluid), Sagging on one corner, Rough ride quality or excessive body roll, Pulsation pump running constantly
Fix: If optioned with ABC instead of Airmatic, the hydraulic suspension lines, accumulators, and pulsation dampeners fail. The system is complex and expensive—leaking lines at struts, pump failure, or valve block issues all common. Each strut is 6-8 hours, pump is 8-10 hours. This is a wallet-draining system.
Estimated cost: $4,000-8,000+ depending on component
COMAND Infotainment Freezing and Hard Drive Failure
Occasional · low severity
Symptoms: Screen freezes or goes black randomly, Navigation won't load or shows incorrect location, Audio cuts out intermittently, System takes 5+ minutes to boot, Complete failure to turn on
Fix: The COMAND head unit's hard drive fails or the system board develops solder joint issues. Sometimes fixed with software update, but usually requires head unit replacement or repair. 2-3 hours labor to remove and reinstall. Aftermarket repair services available at fraction of dealer cost.
Estimated cost: $800-2,500
Owner tips
Send oil samples to Blackstone Labs every 5,000 miles to catch bearing wear before catastrophic M157 failure—look for elevated aluminum and bearing material
Change transmission fluid every 40,000 miles despite Mercedes 'lifetime fill' claim—use genuine MB 236.14 spec fluid only
Budget $3,000-5,000 annually for maintenance and repairs after 60,000 miles; this is not a cheap car to own
Find a Mercedes specialist or independent with Star Diagnostics—dealer rates will bankrupt you on these
Seriously consider extended warranty coverage that includes engine—the M157 issue alone justifies it
Only buy if you have a $20K emergency fund or comprehensive warranty—the M157 engine is a ticking time bomb that can grenade without warning, and repair costs exceed the car's value once it happens.
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; high-performance V8 BiTurbo requires high CCA rating
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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 2014 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.