Mercedes-Benz ML 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.
Adequately Powered
200 kW in an SUV is adequate. Not exciting, but not underpowered either.
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
Water enters through defective tail light seals and damages the rear SAM module. Mainly pre-facelift models up to 2008 are affected.
Airmatic air struts develop leaks, particularly at certain ride height settings. The compressor pumps continuously and eventually burns out.
The 7G-Tronic transmission control unit develops faults at higher mileages. Gear engagement becomes impossible, limp mode activates.
Aluminium steering rack bolts corrode due to road salt. If all three bolts fracture, power steering fails completely. KBA recall 012425.
Pressure reservoir, compressor and air bags are highly vulnerable. Vehicle drops on one side or completely. Repair costs are very high due to expensive original parts and high labour rates.
Brake lines under the rear axle are prone to corrosion, particularly in high-salt regions. Line clips encourage moisture accumulation. Replacement requires lowering the rear axle.
The rear SAM fails when water enters through tail lights. Result: failure of lighting, wipers and displays. Mainly pre-facelift models up to 2008 affected.