The 2022 W213 E350 with OM654 diesel is relatively new, but the OM654 engine family has shown catastrophic piston/bearing failures in a small subset of units, plus typical Mercedes transmission and emissions system issues that plague modern diesels.
OM654 Catastrophic Engine Failure (Piston/Bearing Damage)
Rare · high severityTypical onset: 20,000-80,000 mi
Symptoms: Sudden metallic knocking or rattling from engine bay, Loss of power and check engine light, Metal shavings in oil during routine changes, Engine seizure in worst cases
Fix: Complete engine rebuild or short block replacement required. This is a known issue with OM654 units—aluminum pistons fail prematurely due to thermal stress or manufacturing defects. Expect 25-35 labor hours for short block swap, more if internals damaged cylinder walls. Mercedes has extended warranty coverage on some VINs.
Estimated cost: $12,000-18,000
9G-Tronic Transmission Oil Cooler Leaks
Occasional · medium severityTypical onset: 40,000-90,000 mi
Symptoms: Transmission fluid spots under vehicle (red fluid), Transmission temperature warning on dash, Harsh or delayed shifts when fluid runs low, Visible wetness around cooler lines at radiator
Fix: Oil cooler or its lines crack due to heat cycling and vibration. Requires cooler replacement, line refresh, and full transmission fluid flush. 4-6 hours labor depending on access and whether auxiliary cooler is involved.
Estimated cost: $1,200-2,200
Diesel Exhaust Fluid (DEF) System Faults
Common · medium severityTypical onset: 50,000-100,000 mi
Symptoms: DEF quality poor warning on cluster, Engine derate or refusal to start after warning countdown, DEF heater fault codes, Crystallized DEF around tank filler neck
Fix: DEF tank heaters, level sensors, and injectors fail from contamination or electrical corrosion. Diagnosis takes 1-2 hours; sensor/heater replacement 3-5 hours; full tank replacement can hit 8-10 hours. Use only top-tier DEF to minimize risk.
Estimated cost: $800-3,500
Transmission Mount Failure
Occasional · low severityTypical onset: 60,000-120,000 mi
Symptoms: Clunk or thud on hard acceleration or deceleration, Excessive vibration at idle in Drive, Visible torn rubber or fluid leaking from hydraulic mount
Fix: The W213 uses a hydraulic transmission mount that deteriorates from oil and heat exposure. Replacement is straightforward—support transmission, unbolt mount, install new unit. 1.5-2.5 hours labor.
Estimated cost: $400-700
Fuel Filter Clogging and Water Contamination
Common · medium severitySymptoms: Hard starting or extended cranking, especially in cold weather, Loss of power under load or hesitation, Fuel filter warning light or water-in-fuel alert, Rough idle or misfires
Fix: Modern diesels are sensitive to fuel quality. Water in diesel causes corrosion and injector damage. Filter should be changed every 20,000 mi; if contaminated, drain water separator and replace filter immediately. 1-1.5 hours labor. Neglect can ruin injectors ($3,000+ per set).
Estimated cost: $250-450
EGR Cooler and Valve Carbon Buildup
Occasional · medium severityTypical onset: 70,000-130,000 mi
Symptoms: Check engine light with EGR flow codes (P0401, P0404), Black smoke on acceleration, Reduced fuel economy, Rough idle or stalling
Fix: Carbon accumulation clogs EGR passages and valve. Cleaning is labor-intensive (4-6 hours) involving intake manifold removal. If cooler is cracked, replacement adds cost. Some shops recommend EGR delete for off-road use only—not legal for street vehicles.
Estimated cost: $900-2,000
Good highway cruiser with excellent fuel economy, but the OM654 engine failure risk and complex emissions systems make this a gamble unless you have extended warranty coverage or deep pockets for a potential rebuild.
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.