The E350 represents the top petrol four-cylinder in the W213 E-Class range, pairing the revised M264 2.0-litre turbo with a 48V mild hybrid system that adds 14 hp of electric boost. Available from 2019 (coupe/cabrio first, sedan from 2020 facelift), it produces 299 hp and 400 Nm through the smooth 9G-Tronic nine-speed automatic. The M264 is a substantial evolution of the earlier M274, with improved internals, but brings 48V system complexity and a known exhaust valve durability concern.
Strong 299 hp with smooth delivery
Refined ride and premium interior
Exhaust valve seat wear concern
48V system adds failure points
Buy if: You want a powerful and refined executive sedan and can find one with complete dealer service history and no misfire codes.
Avoid if: You want the simplest possible ownership experience or are uncomfortable with 48V mild hybrid system complexity.
Expected Annual Maintenance Costs
Common Problems
Exhaust valve guides and seats wear prematurely, causing misfires and potential cylinder head replacement · more· less
The M264 engine has a documented defect involving premature wear of the exhaust valve guides and seat rings. Increased lateral forces during operation cause the valve guides to wear beyond specification, leading to poor valve sealing. Symptoms include engine misfires (typically codes P0300-P0304), rough idle, check engine light, and in severe cases, sudden power loss. The issue can appear as early as 50,000 km, though most failures occur between 60,000-100,000 km. Mercedes-Benz USA has extended warranty coverage to 15 years / 240,000 km for the exhaust valve system on 2018-2023 M264 engines. European warranty extension has not been officially confirmed to the same extent, but dealers have been performing goodwill repairs in documented cases. If not covered, cylinder head replacement costs €3,000-5,000 at an independent specialist and €5,000-7,000 at a Mercedes dealer. A class action investigation is ongoing in the US. When buying, always scan for misfire codes and check whether the cylinder head has already been replaced.
48V lithium-ion battery degrades, causing start-stop malfunction, warning messages, and reduced hybrid function · more· less
The EQ Boost system relies on a 48V lithium-ion battery that powers the integrated starter-generator and provides the electric boost function. The battery can degrade over time, causing 'Hybrid System Error' warnings, disabled start-stop, weak acceleration from standstill, and in some cases vehicle stalling. Multiple owners have reported failures within 3-5 years. A class action lawsuit has been filed in the US over repeated 48V battery failures across Mercedes models. Battery replacement costs approximately €1,500-2,500 including labor, as the unit is sealed and requires dealer-level diagnostics for initialization. The battery is expected to last 6-8 years under normal conditions, but hot climates and extended parking periods accelerate degradation. Ensure the start-stop system functions correctly during any test drive.
Direct injection allows carbon deposits on intake valves, causing rough idle and reduced performance after 60,000 km · more· less
Like all direct injection engines, the M264 does not wash fuel over the intake valves. Oil vapors from the crankcase ventilation system bake onto valve surfaces over time, restricting airflow. Symptoms include rough idle, hesitation under acceleration, and increased fuel consumption. The buildup becomes noticeable between 60,000 and 80,000 km depending on driving patterns. Short trips and frequent cold starts accelerate the problem. Walnut shell blasting is the standard cleaning method, costing €500-900 at an independent specialist for a four-cylinder engine. This is considered preventive maintenance by most specialists and is recommended every 60,000-80,000 km. Regular motorway driving and using premium fuel help slow the buildup but cannot prevent it entirely.
Transmission exhibits jerky low-speed shifts, gear hunting, or delayed engagement, especially when cold · more· less
The 725.0 9G-Tronic nine-speed automatic can develop jerky shifting behavior, particularly at low speeds between 1st-2nd and 2nd-3rd gears. Symptoms include harsh downshifts when slowing, hesitation when moving from neutral to drive, and occasionally delayed gear engagement. In many cases, a TCU software update from a Mercedes dealer resolves the issue (€200-400). However, if the valve body or mechatronic unit has degraded, repair costs increase significantly to €1,200-2,000. Regular ATF changes every 60,000-80,000 km help maintain smooth operation, despite Mercedes marketing the fluid as a lifetime fill. If ignored, shifting issues can progress to limp mode. During any test drive, pay attention to low-speed shifting quality over at least 20 minutes of varied driving.
Optional air suspension develops leaks, causing uneven ride height and compressor overwork · more· less
AIRMATIC is optional on the E350 (standard on AMG models). If your car is equipped with it, the rubber air springs become brittle over time and develop micro-cracks. Symptoms include one corner sitting lower after overnight parking, the compressor running constantly, or suspension warning messages. Failure typically occurs after 80,000-120,000 km. OEM replacement per spring costs €600-900, with aftermarket alternatives from Arnott available for €300-500 per spring. The compressor can fail from overwork, adding €500-900 for replacement. A full overhaul (4 springs plus compressor) at a dealer can reach €3,000-3,500. Some owners convert to conventional coil springs as a permanent solution for around €800-1,200. If the car has steel springs, this issue does not apply.
M264 engines may consume up to 0.5L per 1,000 km, with worse cases indicating internal wear · more· less
Mercedes considers oil consumption of up to 0.5 litres per 1,000 km as normal for the M264 engine. Some owners report consumption exceeding this threshold, particularly on pre-2021 production engines. Causes include worn piston rings, valve stem seal degradation, or PCV system malfunction. If consumption is excessive (more than 1L per 2,000 km), a compression test and borescope inspection are recommended. PCV system repair costs approximately €500-800. Valve stem seal replacement runs €1,200-1,800. Piston ring replacement requires engine disassembly at €2,000-2,500. Regular oil level monitoring between services is essential. Using the correct MB 229.51 or 229.61 specification oil and maintaining 15,000 km or shorter change intervals helps preserve internal seal integrity.
Generally solid, but the exhaust valve defect and 48V system need attention
The M264 is a newer engine with fewer long-term data points than predecessors like the M274 or M271, but it is fundamentally well-engineered. The most significant concern is the exhaust valve seat and guide wear defect, which Mercedes has acknowledged through a warranty extension in the US. For European buyers outside warranty, this represents a potentially expensive repair. The 48V EQ Boost system adds mild hybrid benefits but also introduces battery and ISG failure points not found on conventional engines. Cars with AIRMATIC suspension carry additional long-term costs. With a complete service history and no misfire codes, the E350 W213 can be a rewarding ownership experience.
Recalls and Technical Service Bulletins
Turbocharger oil feed/return line screws (2019-2020 production with M264 engine)
Verify completed
Fuel pump impeller deformation - loss of drive power (2021-2023 models)
Critical - verify completed
Rear seat belt automatic locking retractor deactivation (2021 models)
Verify completed
Exit warning system software error (2023 models)
Verify completed
Contact a Mercedes-Benz dealer with the VIN to verify all recalls have been completed. The fuel pump recall (2021-2023 models) is particularly important as it can cause sudden loss of drive power. Also ask about the M264 exhaust valve warranty extension status for your specific car.
Warranty Status
Factory warranty (2 years)
Expired on 2019-2023 models (may still apply to late 2023 cars)
Exhaust valve extended warranty (US: 15 years / 240,000 km)
Confirmed in US; ask dealer about European coverage
Rust perforation warranty (30 years)
Active on all W213 models
Most used E350 W213 models are outside their original 2-year factory warranty. The M264 exhaust valve warranty extension to 15 years / 240,000 km has been confirmed by Mercedes-Benz USA. European coverage has not been publicly announced to the same extent, but Mercedes dealers have performed goodwill repairs in documented cases. Contact a Mercedes-Benz dealer with your VIN to check your specific car's eligibility.
This report is for informational purposes only and does not constitute professional advice. Estimates may be inaccurate. Always have a qualified specialist inspect the vehicle before purchase. We accept no liability for decisions made based on this information.