Mercedes-Benz E 300
Current four-cylinder turbo with 48V mild hybrid and integrated starter-generator (ISG). Higher output than predecessor at lower consumption. Also used as PHEV base (CLE 300e).
Solid baseline
190 kW — adequately powered for everyday use, nothing more.
Engine Weaknesses 6
Early M254 production batches 2021–2023 show elevated oil consumption due to insufficient piston ring sealing. Mercedes repair involves engine reconditioning.
Symptoms: Dropping oil level between services, bluish smoke on cold start, consumption above 0.5 L/1,000 km
The M254 exhibits timing chain rattle at cold start when oil change intervals are missed. Chain tensioner sealing rings can leak and lose tension. Engine damage is possible.
Symptoms: Rattling or clattering from the engine bay at cold start, disappears after warm-up, worsens with extended service intervals
Defective exhaust valves and guides in the M254 lead to misfires and cylinder head damage. Mercedes USA extended the warranty to 15 years/150,000 miles; no official recall in Germany.
Symptoms: Sudden power loss, severe misfires, CEL flashing, rough engine, dangerous misfires at motorway speed
The 48V mild-hybrid system with integrated starter-generator shows malfunctions: start-stop problems, fault messages and in extreme cases 48V battery failure.
Symptoms: Start-stop system deactivated, EQ Boost warning, hybrid system fault memory, starting problems
The M254 runs three separate electric coolant pumps. Pump failures trigger fault codes P0A05, P00B7, and P0C73. Bleeding requires the Mercedes diagnostic tool.
Symptoms: Coolant temperature warning symbols, insufficient coolant flow, irregular engine temperature, fault codes P0A0500/P00B700/P0C7300
Direct injection without port injection leads to carbon deposits after 50,000–70,000 km. Regular walnut blasting recommended.
Symptoms: Hesitation at part throttle, rough idle, slight overconsumption
Vehicle Weaknesses 6
Faulty MBUX software can deactivate lane-keep assist and emergency braking assistant. Affects production 10.11.2021–29.01.2024.
MBUX 3.0 shows complete screen blackouts with loss of climate control, navigation and vehicle functions while driving.
MBUX 3.0 starts in emergency mode with barely any functions available. Spotify/Apple Music show only a loading screen. Mainly affects early production vehicles from 2023.
The optional AIRMATIC air suspension is prone to pressure loss at the air spring bellows or pressure hoses. Vehicle sags on one side.
MBUX 3 system can fail completely — only the speedometer remains functional. Spotify, Apple Music and navigation fail to load. Software updates are applied regularly.
Rattling noises from doors and interior trim appear shortly after delivery. Individual vehicles with heavily rattling passenger door from the factory.