The 2021 E350 W213 with the M264 2.0L turbo four is generally solid but shows catastrophic engine failure tendencies tied to oil starvation and balance shaft module issues, mostly under 60k miles. When they fail, it's spectacular and expensive—think complete engine replacement territory.
M264 Balance Shaft Module Failure Leading to Catastrophic Engine Damage
Occasional · high severity
Typical onset: 30,000-60,000 mi
Symptoms: Sudden severe knocking or rattling from lower engine, Metal shavings in oil during routine changes, Oil pressure warning light, Complete loss of power / engine seizure in worst cases
Fix: Balance shaft module grenades and sends metal through the entire oiling system, scoring bearings and cylinder walls. Almost always requires complete engine replacement or rebuild with all bearings, pistons, rings, and thorough block inspection. 25-35 hours labor for engine replacement.
Estimated cost: $15,000-22,000
Transmission Oil Cooler Line Leaks
Common · medium severity
Typical onset: 40,000-80,000 mi
Symptoms: Transmission fluid pooling under vehicle front, Burnt transmission fluid smell, Harsh shifting or slipping when fluid level drops, Low transmission fluid warning on dash
Fix: The quick-connect fittings on cooler lines corrode or the rubber sections crack. Replace affected lines and top off fluid. Some cases require full cooler replacement if internal failure. 2-4 hours labor depending on access.
Estimated cost: $600-1,400
Transmission Mount Collapse
Common · low severity
Typical onset: 50,000-90,000 mi
Symptoms: Clunk when shifting from Park to Drive or Reverse, Excessive vibration at idle, Drivetrain slap on hard acceleration, Visible tearing or fluid leaking from mount
Fix: The hydraulic transmission mount deteriorates and loses its damping ability. Replacement is straightforward—support the trans, unbolt old mount, install new OE or aftermarket. 1.5-2.5 hours labor.
Estimated cost: $450-750
Fuel Filter Clogging (Early Production Units)
Occasional · medium severity
Typical onset: 20,000-50,000 mi
Symptoms: Rough idle or hesitation under load, Check engine light with lean fuel trim codes, Hard starting after sitting, Loss of power on highway acceleration
Fix: Some early 2021s left the factory with contaminated fuel systems or poor-quality filters. Replace in-tank fuel filter and pump assembly if contaminated. Labor intensive due to tank drop. 3-5 hours labor.
Estimated cost: $800-1,600
Turbocharger Wastegate Rattle
Occasional · low severity
Typical onset: 40,000-70,000 mi
Symptoms: Metallic rattle on cold start that disappears when warm, Rattle audible during light throttle acceleration around 1,500-2,500 RPM, No performance loss initially, May eventually throw underboost codes
Fix: Wastegate actuator arm develops play or the flapper valve wears. Can sometimes be addressed with actuator replacement alone, but often requires turbo R&R and rebuild or replacement. 6-8 hours labor for turbo replacement.
Estimated cost: $2,200-3,800
Coolant Thermostat Housing Leak
Occasional · medium severity
Typical onset: 60,000-100,000 mi
Symptoms: Coolant weeping from front of engine, Sweet coolant smell in cabin or engine bay, Slow coolant loss over time, Overheating if neglected long enough
Fix: Plastic thermostat housing cracks at mounting points or seals fail. Replace entire housing assembly with updated part. Requires coolant drain and refill with proper MB coolant. 2-3 hours labor.
Estimated cost: $500-900
Owner tips
Change oil every 5,000 miles maximum with MB 229.52 spec oil—the M264 is sensitive to oil quality and the balance shaft module depends on clean oil flow
Inspect transmission fluid color and level every 20k miles; dark or burnt fluid means cooler issues starting
Use Top Tier fuel exclusively; these direct-injection engines are sensitive to injector deposits
Budget $1,000/year for unexpected repairs after 50k miles; when M264s fail, they fail big
Great car when it works, but the M264 engine is a ticking time bomb—only buy with full MB service history and a comprehensive warranty, or be prepared to gamble on a $20k engine replacement.
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 required for start-stop system; located in trunk; auxiliary battery also present
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Every control module on the 2021-2024 Mercedes-Benz E350 W213 — 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.
Electric Power Steering Control Unit (EPS)2.8 hr R&Rsecurity gateway +1.0 hr▸ programming details
📍 Steering column, integrated with steering rack
🔧 Xentry Diagnostics + SCN online
⚠️ Requires steering angle sensor calibration and wheel alignment after replacement.
Transmission Control Unit (TCU)2.5 hr R&Rsecurity gateway +1.0 hr▸ programming details
⚠️ Memory seat settings lost. Relearn procedure available with most scan tools.
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 2021 Mercedes-Benz E350 W213 2.0L I4 Turbo M264 and can vary by trim.
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Mechanic · 20+ years.