The 2009 E63 AMG with the M156 6.2L V8 is a high-performance sedan with one catastrophic weakness: the engine's head bolt design leads to cylinder head lifting and cracked cylinder walls, typically requiring complete engine rebuilds. When the motor stays intact, it's a solid performer, but that head bolt issue looms over every example.
M156 Head Bolt Failure and Cylinder Wall Cracking
Common · high severity
Typical onset: 50,000-90,000 mi
Symptoms: Coolant consumption with no external leaks, White smoke from exhaust on cold start, Misfires on specific cylinders (often 7 or 8), Overheating under load, Milky oil or coolant in expansion tank
Fix: Factory head bolts are too short and allow head lift under high cylinder pressures. Heads warp, crack block sleeves, wash bearings. Proper fix requires engine-out complete rebuild with aftermarket studs, block sleeving or replacement, new pistons, bearings, gaskets. 40-60 hours labor.
Estimated cost: $18,000-28,000
Transmission Oil Cooler Line Leaks
Common · medium severity
Typical onset: 70,000-120,000 mi
Symptoms: Transmission fluid drips under engine area, Low fluid level warnings on dash, Burnt smell after driving, Harsh or delayed shifts when fluid gets low
Fix: Metal cooler lines running along the side of the transmission develop pinhole leaks from road salt and debris. Lines should be replaced as a set, not patched. 3-4 hours labor, requires transmission pan drop and fluid service.
Estimated cost: $800-1,400
Transmission Mount Collapse
Common · medium severity
Typical onset: 60,000-100,000 mi
Symptoms: Excessive clunk on 1-2 or 2-3 upshifts, Vibration at idle in Drive, Driveline shudder during acceleration, Visible drooping of transmission tailshaft
Fix: The rear transmission mount (often called the tailshaft mount) fails from the aggressive torque and frequent full-throttle runs. Rubber tears internally. Replace with OE or upgraded polyurethane unit. 1.5-2 hours on a lift.
Estimated cost: $400-700
Camshaft Adjuster Solenoid Failures
Occasional · medium severity
Typical onset: 80,000-130,000 mi
Symptoms: Check engine light with cam position correlation codes (P0016, P0017, P0018, P0019), Rough idle when engine is warm, Rattle on startup for 2-3 seconds, Slight loss of power in mid-range
Fix: VVT solenoids stick or fail, throwing timing codes. Sometimes cleaning helps temporarily, but replacement is the reliable fix. Four solenoids total (intake and exhaust per bank). 2-3 hours labor, requires valve cover removal.
Estimated cost: $900-1,600
Alternator Bearing and Regulator Failure
Occasional · medium severity
Typical onset: 90,000-140,000 mi
Symptoms: Squealing or grinding from front of engine, Battery warning light intermittent or steady, Voltage fluctuations (below 13V or above 15V), Multiple electrical faults stored in system
Fix: High-output alternator (200+ amps) works hard and bearings or voltage regulator fail. Replacement is typical, rebuilds are hit-or-miss. Serpentine belt off, two bolts, electrical connectors. 1.5 hours labor.
Symptoms: Metallic rattling from deep in engine at idle, Metal shavings in oil during changes, Rough vibration that worsens over time, Catastrophic engine noise if gear teeth strip
Fix: Early M156 engines had weak balance shaft gears that could strip teeth and send metal through the engine. 2009 is borderline; some had the updated parts, some didn't. Requires engine disassembly to inspect and replace gears and chains. 25-35 hours if caught early, total loss if it grenades.
Estimated cost: $8,000-15,000
Owner tips
Check build date and engine serial to verify if balance shaft update was done—critical on 2009 models
Use full synthetic 0W-40 oil and change every 5,000 miles religiously—the M156 runs hot and burns oil by design
Inspect coolant level monthly; any consumption is an early warning of head bolt problems
Budget $2,000/year maintenance minimum if buying used; $20k engine rebuild reserve if past 60k miles
Avoid cars with track history or heavy modifications—head bolt failure risk climbs exponentially with tune or forced induction
Only buy if you can afford a $20k engine rebuild or find a rare example with documented head stud upgrade—otherwise, it's a ticking time bomb wrapped in a brilliant chassis.
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 auxiliary battery (e.g. MB P/N A0009829608; equivalent to Mercedes AUX-class backup battery) · Location: Engine compartment, right (passenger) side near the firewall/cowl area; the main 12V starter battery is separate, in the right-side trunk well · Purpose: Voltage support / electrical system backup — maintains stable voltage for sensitive electronics and the SBC (Sensotronic Brake Control) system during cranking and low-voltage conditions
As an Amazon Associate and Autel/ANCEL partner, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.
Control Modules — 2009 Mercedes-Benz E63 AMG
Every control module on the 2008-2011 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.
⚠️ Requires subscription activation after replacement.
Bi-Xenon Control Unit (XCU)0.6 hr R&Raftermarket tool +0.2 hr▸ programming details
📍 Behind each headlight assembly (left and right)
🔧 Star Diagnosis or Autel
⚠️ Headlight 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 2009 Mercedes-Benz E63 AMG 6.2L V8 M156 and can vary by trim.
🔧 Built by master technician Chris Hackleman · Master Technician · 20+ years.