Mercedes-Benz R 350
Four-valve V6 with variable valve timing. Smooth and powerful. Known for balance shaft wear (revision sprocket) on early build years. Balance shaft gear problem addressed by Mercedes with a recall.
Solid Basis
200 kW — everyday-capable power, without excitement.
Engine Weaknesses 6
The plastic balance shaft sprocket on the M272 wears prematurely from the timing chain. The right cylinder bank goes out of timing. Affected up to end of October 2006.
Symptoms: Fault codes P0016/P0017 (camshaft right bank), chain rattling, rough running at idle, in extreme cases engine damage
Alongside the balance shaft issue the M272 shows premature timing chain stretch. Chain wear on softer sprockets leads to timing deviations.
Symptoms: Chain noise especially on cold start, camshaft fault codes, rough running, engine irregularities
Four camshaft adjuster solenoids (two per cylinder bank) develop leaks; oil creeps into the wiring harness as far as the ECU. Repair costs up to €1,700 documented.
Symptoms: CEL, oil traces at camshaft connectors, lambda sensor failure due to oil contamination, non-specific faults that recur
Plastic components of the M272 variable intake system become brittle and break. The intake flap linkage snaps and sets fault code P2006.
Symptoms: Fault codes P2004/P2005/P2006 (intake flap), slight power loss, check engine light
The thermostat on the M272 preferentially fails in the open position. Operating temperature is not reached; especially on motorway runs temperature drops to 75–80°C.
Symptoms: Engine doesn't reach 90°C after 10–20 km, coolant temperature fluctuates heavily, reduced heater output, fault code P0128
The hydraulic engine mounts on the M272 lose their damping effect with age. Jerky movements are especially apparent when lifting off the throttle and during gear changes.
Symptoms: Vibrations in steering wheel and gear lever during load changes, judder on gear changes, droning at low revs
Vehicle Weaknesses 7
The Airmatic air spring bellows develop leaks and cause the vehicle to sink. The vehicle sits lower on one side when parked. Arnott replacement bellows approximately €200; workshop costs up to €1,900.
The 7G-Tronic gearbox does not pair well with diesel models; gearbox calibration is rough. At higher mileages torque converter defects occur; 3rd and 4th gear clutches burn out. Gearbox oil flush every 60,000 km recommended.
The Airmatic air suspension compressor wears at high mileage, particularly if the air spring bellows were already leaking and the compressor had to run continuously. Replacement compressor €400–700; expensive to fit.
Design-related water ingress into the boot or footwell damages connectors. Rear SAM control unit costs approximately €1,100 and fails when wet.
Rust appears on doors and black-painted chassis components. First two model years (2005–2006) particularly prone. Improved from 2008/2009 onwards. Avoid early vehicles if possible.
Doors and tailgate show rust perforation even on younger examples. Water ingress via defective seals promotes corrosion from the inside. Body shops quote €1,500–3,200.
The sunroof motor and gearbox skip and jam. Weak on-board electrical system due to battery problems. Steering knocks from worn joints. Wind noise from poorly seated seals.