Mercedes-Benz E 300
Four-cylinder turbo with 48V belt starter-generator. Modern, efficient engine with EQ Boost mild hybrid. Timing chain long-lived.
Roadster Pragmatism
190 kW in the roadster — enough for open-top enjoyment on summer days.
Engine Weaknesses 12
Defective exhaust valves and soft valve guides lead to severe cylinder head damage. Often just after the warranty expires. Mercedes USA extended the warranty to 15 years/150,000 miles.
Symptoms: Sudden severe misfires, CEL flashing, power drop, dangerous stalling at motorway speed
The electric motor is integrated into the 9G-Tronic. With faults in the high-voltage cables the gearbox must be removed — extremely costly repair.
Symptoms: Fault message 'Hybrid drivetrain disturbed', no electric drive possible, vehicle runs as pure combustion engine only, sometimes emergency shutdown
The hydraulic chain tensioner on the M264 can lose oil pressure after extended standstill. On cold start the timing chain rattles briefly until oil pressure builds.
Symptoms: Brief rattling on cold start (2–5 seconds), disappears after warm-up
The integrated starter-generator (ISG) of the M264 EQ Boost system can fail. Start-stop function and boost support are lost. Expensive replacement.
Symptoms: Start-stop function deactivated, no EQ Boost on pull-away, 48V system fault message, rougher engine start
The M264 uses multiple electric coolant pumps. Internal motor defects trigger fault codes. Bleeding requires the Mercedes diagnostic tool.
Symptoms: Coolant temperature warning, fault codes P0A0500/P00B700/P0C7300, irregular engine temperature
The PHEV lithium-ion battery measurably loses capacity at high mileage. Faulty temperature sensors can trigger emergency shutdown of the hybrid drivetrain.
Symptoms: Electric range drops significantly, warning 'Stop immediately', unexpected shutdown of hybrid drivetrain
The 48V lithium-ion battery of the EQ Boost system loses capacity over time. With severe degradation the boost function is curtailed.
Symptoms: Reduced EQ Boost output, more frequent start-stop deactivation, 48V warning on display
The camshaft adjuster solenoid valves on the M264 can leak internally. Variable timing no longer functions correctly, engine runs rough.
Symptoms: Rough idle, camshaft position fault codes, slight power loss in the lower rev range
Direct injection without port injection leads to carbon deposits on intake valves, especially with short-trip use. Impairs intake flow and combustion.
Symptoms: Hesitation and rough idle from approx. 80,000 km, slight power drop, elevated fuel consumption, knock tendency under load
The OPF requires temperatures above 600°C for active regeneration. With frequent short trips under 10 km the filter cannot regenerate and becomes progressively blocked.
Symptoms: Check engine light, elevated fuel consumption, forced long-distance drive needed for regeneration, engine power reduced
Turbocharging and direct injection thermally stress spark plugs more heavily. Ignition coils can electrically fatigue at high mileage and cause misfires.
Symptoms: Misfires, rough engine running, hesitation on acceleration, check engine light, poor throttle response
Valve cover gasket and rear crankshaft seal tend to leak at higher mileage. Oil loss on the hot engine can cause smoke.
Symptoms: Oil smell when parked, visible oil puddles under the vehicle, dropping oil level, bluish smoke from engine bay
Vehicle Weaknesses 16
An incorrectly routed gearbox wiring harness allows water ingress with an increased fire risk. Mercedes issued a recall.
Following software updates, the ECU in individual C238 units was permanently damaged. One owner reported a seven-month workshop stay.
A serial design defect: the tension cables in the soft-top headliner fray and snap after approximately 200–300 roof cycles. Mercedes revised the design from May 2020.
The electric parking brake generates fault messages and seizes, particularly in cold weather. Grinding noises when applying indicate worn components.
The soft-top tension cords fray after just a few hundred opening cycles. A design fault that led Mercedes to carry out goodwill repairs.
At higher mileages the electric motors in the roof kinematics or the hydraulic unit can fail. The roof can then no longer open or close fully.
Brake discs on the W213 show juddering after just a few thousand kilometres. Individual cases report renewed juddering after warranty replacement.
Elevated MOT failure rates at suspension mounts. The double wishbone front axle shows wear at bearings and joints.
Infotainment and driver assistance systems are prone to faults. Brake assist and cruise control warning messages appear without cause. Often resolved via software update.
The electric parking brake is prone to corrosion and seizing. Multiple recall actions for the brake system have been documented.
The electric parking brake generates fault messages and seizes, especially in cold weather. Grinding and creaking noises when releasing are common.
The optional Airmatic air suspension is prone to compressor and air bag failures. Replacement requires removal of the rear axle and is expensive.
The headliner tension cords fray and snap after approximately 200–300 roof cycles. Design fault present until the facelift in 05/2020. Mercedes repair approx. 1,200 EUR, upholstery shop approx. 300 EUR.
The rotary push controller on the centre console is mechanically fragile and shows signs of failure after heavy use.
MBUX system freezes or reboots. Bluetooth connections drop, voice control unresponsive. Software updates only fix some issues.
Hollow-section seals at the side window frame collect rainwater. When the door is opened the collected water runs onto the seat. Particularly with the Easy Entry function.