The 2017 E63 AMG with the M177 4.0L twin-turbo V8 is a phenomenal performer that unfortunately suffers from catastrophic engine bearing failures, particularly connecting rod bearings, often without warning and sometimes under warranty mileage. When they let go, you're looking at complete engine destruction requiring short block replacement or full rebuild.
Connecting Rod Bearing Failure (M177 Engine)
Occasional · high severityTypical onset: 20,000-60,000 mi
Symptoms: Metallic knocking or rattling from engine bay, especially on cold start, Metal shavings in oil during analysis, Sudden catastrophic failure with no prior warning in some cases, Check engine light with low oil pressure codes
Fix: Complete engine-out short block replacement is typical because bearing debris contaminates everything. Expect 35-45 labor hours for short block R&R plus machine work if salvaging heads. Some owners catch it early with oil analysis and can get away with bearing replacement alone (25-30 hours), but collateral damage is common.
Estimated cost: $18,000-32,000
Transmission Oil Cooler Leaks
Common · medium severityTypical onset: 40,000-80,000 mi
Symptoms: Transmission fluid pooling under vehicle, front-center location, Low transmission fluid warning on dash, Burnt transmission fluid smell, Harsh shifting or slipping if driven low on fluid
Fix: The external oil cooler develops pinhole leaks at the crimped seams or line connections. Cooler replacement requires dropping the subframe for access, approximately 6-8 hours labor. Must flush transmission system and refill with fresh MB-spec ATF.
Estimated cost: $1,800-2,800
Transmission Mount Failure
Common · medium severityTypical onset: 50,000-90,000 mi
Symptoms: Clunking when shifting from Park to Drive/Reverse, Excessive drivetrain movement felt through chassis during acceleration, Vibration at idle that worsens with load, Visible tears or separation in rubber mount material
Fix: The 9-speed transmission mount fatigues from the high torque (over 700 lb-ft in S model). Replacement requires supporting transmission and subframe work, about 3-4 hours. Use OEM mounts only—aftermarket versions fail quickly under this power.
Estimated cost: $800-1,400
Turbocharger Wastegate Rattle
Occasional · low severityTypical onset: 30,000-70,000 mi
Symptoms: Rattling noise from engine bay at idle or light throttle, Sound disappears under boost or when engine is cold, No performance loss or check engine light initially, Can progress to boost control issues if ignored long-term
Fix: The wastegate actuator arms develop play in the bushings, creating rattle. Early cases can be lived with; severe cases need turbocharger removal and actuator replacement or rebuild. Each turbo is about 8-10 hours labor due to tight packaging in the V8.
Estimated cost: $3,500-5,500
Fuel Injector Failure
Occasional · medium severityTypical onset: 60,000-100,000 mi
Symptoms: Rough idle or misfires on specific cylinders, Check engine light with fuel trim or misfire codes, Hesitation or stumble during acceleration, Fuel smell from engine bay in severe cases
Fix: Direct injection piezo injectors fail electrically or develop internal leaks. Testing requires scan tool with live injector data. Replace failed injector(s) and perform adaptation—about 2 hours per injector on this engine due to intake manifold partially blocking access. Always replace in pairs per bank for even wear.
Estimated cost: $1,200-2,000
Airmatic Suspension Leaks
Common · medium severityTypical onset: 60,000-100,000 mi
Symptoms: Vehicle sitting low, especially after sitting overnight, Compressor running excessively (can hear it cycling), Suspension warning light on dash, Uneven ride height side-to-side
Fix: Air struts develop leaks at the upper mounts or through the airbag material itself. Compressor can also fail from overwork. Strut replacement is 2-3 hours per corner; compressor is about 3 hours. Don't ignore—a seized compressor from running dry will double your repair bill.
Estimated cost: $1,500-3,000
Only buy if you have $20,000+ in reserve for a potential engine replacement and can stomach the risk—when they're good they're incredible, but the M177 bearing issue is a ticking time bomb that Mercedes never fully resolved.
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.