E 350 CDI OM642, known issues
W212 · 2009–2016 · R3 Demands diligence
Recorded issues8
Walk-away0
Over €1,0004
Checkable at viewing4/8
Likely spend€4,300
Likely spend is the mid cost of every issue rated common or universal, added together, what an unmaintained example owes over the next few years, not a prediction for any one car. Worst case if everything here failed at once is €8,400, which isn't a realistic scenario but is a useful ceiling.
All issues, by system
Engine
Oil weeping down the back of the block, burning smell, oil in the valley beneath the intake. The oil cooler sits in the vee under the intake manifold and its seals harden with age. Access requires the intake off, so labour dominates the bill.
Check: Look down the back of the engine with a torch for wet oil and fresh cleaning. A suspiciously spotless engine bay on a 200,000 km V6 deserves a question.
Emissions
Warning light, limp mode, oil level rising above the maximum mark from fuel dilution. The filter needs sustained hot running to regenerate. A car used for short urban trips never completes a regeneration cycle.
Check: Read the DPF soot load and the distance since the last regeneration on a scan tool, and check the engine oil level and smell it for diesel. Ask what the car was used for. A short-trip city diesel is the wrong car regardless of mileage.
Coolant loss with no visible external leak, white smoke, sweet smell. The EGR cooler cracks internally and leaks coolant into the intake. BMW recalled affected diesels over a fire risk from glycol deposits igniting.
Check: Check coolant level and look for unexplained top-ups in the service history. Verify the recall was carried out. It's free and searchable by VIN.
Electrical
The engine cranks but won't start and the steering stays locked, sometimes after several attempts, with steering-lock fault codes. The small motor that drives the locking bolt wears out and the module eventually blocks further attempts. The cause is consistent motor wear rather than anything variable.
Check: Do several cold starts. Listen for the steering-lock clunk as the key goes in, and scan for B2254 and related codes; intermittent no-starts are the early warning.
Transmission
7G-Tronic conductor plate and 13-pin connector leak (722.9)Mercedes 7G-Tronic seven-speed automatic (722.9)€400–€900
Harsh, delayed or jerky shifts, holding a gear then banging the next in, and limp mode, often with speed-sensor or gear-ratio fault codes. The speed sensors in the conductor plate (mechatronic) fail, and/or the external 13-pin connector leaks fluid that wicks up the wiring into the control unit. Early units are the most affected.
Check: Test-drive through every gear cold and warm. Scan the transmission, and pull the external 13-pin plug to check for fluid on the pins.
Suspension
A clunk or knock over bumps and when turning at low speed, vibration through the wheel, and vague or wandering steering. The aluminium front arms use fluid-filled hydraulic bushes that rupture and leak; the bushes aren't separately serviceable, so the whole arm is replaced. The cause is consistent.
Check: Look for brown hydraulic fluid weeping from the bushes, rock the arms for play, and listen for a clunk over rough roads and on full lock.
Turbo & intake
Limp mode and power loss, usually with fault code P2015 stored. The actuator motor that drives the intake-port shut-off flaps in the manifold fails, frequently after being shorted by oil dripping from the turbo-inlet seal above it; the flaps or linkage can also seize.
Check: Scan for P2015 and related intake codes; a car that has thrown it before is likely to again unless the oil-leak cause was addressed.
Body & corrosion
Wet front footwells and carpets and damp A-pillars after rain, with soaked module connectors as the secondary risk. The sunroof drain channels clog with debris and water backs up and overflows into the cabin. The cause is consistent; the cost jumps if carpets or modules are soaked.
Check: Lift the footwell carpets to feel for damp, and pour a cup of water into the front sunroof channel to confirm it drains quickly.
How to read this
Every issue is authored once against the part that actually carries it: the engine, the gearbox, the chassis or a shared component, and inherited by every variant that has that part. The badge next to each issue says where it comes from, so you can tell an OM642 problem from an E9x problem.
Evidence tiers. Manufacturer means a recall, technical bulletin or revised part number. Documented means workshop data or multiple independent sources. Reported means owner consensus with no hard confirmation, and never sets a risk level on its own.