The 2014 E63 AMG with M157 engine is a high-strung performance sedan with serious head bolt and bearing issues that can grenade motors between 60k-100k miles. The 7-speed MCT transmission is generally stout, but auxiliary systems like coolers and mounts wear earlier than the powertrain itself.
M157 Head Bolt Failure Leading to Catastrophic Engine Damage
Common · high severity
Typical onset: 60,000-100,000 mi
Symptoms: Coolant loss with no visible leaks, White smoke from exhaust on cold start, Rough idle that worsens over time, Eventual catastrophic overheating and bearing failure
Fix: Head bolts stretch and allow combustion pressure into coolant passages, contaminating oil and wiping bearings. Proper fix requires complete disassembly: head gasket replacement with updated bolts (if you catch it early, 18-22 hrs), or full shortblock replacement with crank/bearings/pistons if oil contamination occurred (45-60 hrs). Many owners discover this after bearings are already toast.
Estimated cost: $8,000-25,000
Connecting Rod and Main Bearing Failure
Occasional · high severity
Typical onset: 70,000-120,000 mi
Symptoms: Low oil pressure warning at idle when hot, Metallic knocking from lower engine, Metal flakes in oil during changes, Sudden engine seizure in worst cases
Fix: M157 bearings are marginal for the power output, especially with extended oil changes or spirited driving. Once knock starts, it's full teardown: crank polish or replacement, all bearings, typically pistons and rings while you're in there. 50-65 hrs labor, requires engine removal for proper access.
Estimated cost: $15,000-22,000
Transmission Oil Cooler Line Leaks
Common · medium severity
Typical onset: 50,000-90,000 mi
Symptoms: Transmission fluid spots under vehicle, driver's side, Burnt ATF smell after highway driving, Transmission temperature warning on dash
Fix: Quick-connect fittings on cooler lines crack or O-rings fail, especially at front cooler connections. Requires trans cooler line replacement, usually both feed and return while you're in there. 3-4 hrs with undertray removal.
Estimated cost: $800-1,400
Transmission Mount Collapse
Common · low severity
Typical onset: 60,000-100,000 mi
Symptoms: Clunk when shifting from P to D or D to R, Vibration at idle in gear, Drivetrain movement visible when accelerating hard
Fix: The 7-speed MCT makes serious torque and tears rubber mounts apart. Trans mount replacement requires subframe support and partial exhaust removal. 4-5 hrs. Often done with engine mounts at same time.
Estimated cost: $600-1,200
Turbocharger Wastegate Rattle
Occasional · medium severity
Typical onset: 80,000-130,000 mi
Symptoms: Rattling sound at idle or light throttle, disappears under boost, Occasional P0299 underboost codes, Reduced power in extreme cases
Fix: Wastegate actuator arms wear and develop play, causing rattle. Can sometimes be adjusted, but often requires turbo replacement. Each turbo is 8-10 hrs with hotside manifold work. Most replace both if one fails.
Estimated cost: $3,500-6,000 per side
Airmatic Suspension Strut Leaks
Occasional · medium severity
Typical onset: 70,000-110,000 mi
Symptoms: Vehicle sits low on one corner after sitting overnight, Suspension warning on dash, Compressor running constantly
Fix: Air struts develop leaks at seals, typical Mercedes Airmatic issue. Strut replacement per corner is 2-3 hrs, but if compressor is overworked it may fail too (add 3 hrs). Most shops recommend doing both fronts or both rears together.
Estimated cost: $1,200-2,000 per strut
Owner tips
Change oil every 5,000 miles maximum with quality 0W-40 — extended intervals kill M157 bearings
Monitor coolant level religiously; unexplained loss is early warning of head bolt stretch
Transmission fluid and filter every 40k miles to extend MCT life, despite 'lifetime fill' marketing
Budget $3k-5k annually for maintenance and repairs if buying used with 70k+ miles
Only buy if you have a $20k engine-rebuild fund or can walk away from a grenade — these are phenomenal when healthy but M157 reliability is genuinely poor.
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: OEM size: 12V 12Ah AGM (Mercedes auxiliary/backup, e.g. A0019828008 type) · Location: engine bay, right/passenger side near the firewall (main battery is in the trunk, right side well) · Purpose: voltage support during ECO start/stop restarts and backup for electronics
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Every control module on the 2014-2017 Mercedes-Benz E63 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.
⚠️ mbrace system. Requires subscription activation after replacement.
Intelligent Light System Control Unit (ILS)0.6 hr R&Raftermarket tool +0.2 hr▸ programming details
📍 Behind each headlight assembly (left and right)
🔧 Xentry or Autel
⚠️ LED adaptive headlight system. Leveling calibration required. Two modules (left/right).
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 E63 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.