Mercedes-Benz E 400 CDI
Mercedes' first V8 diesel in automotive history — world premiere in 2000. Common rail at 1,350 bar, two turbos in tandem, 4.0 litres. Result: 570 Nm from 1,600 rpm, a character that no petrol engine of that class could match in composure at the time. Maintenance-intensive. Timing chain and tensioners are due around 150,000 km — not optional, mandatory. The right-hand turbocharger is the known weakness and will need replacing sooner or later. Injectors and high-pressure pump dislike poor-quality fuel. Oil every 10,000 km, Mercedes approval 229.51 or better — the engine does not forgive cutting corners on lubricant. With thorough maintenance 300,000 km is realistic. None of this is cheap, but anyone who buys a V8 diesel budgets for it.
V8 Diesel in Mid-Size Clothing — Rare Find
The W211 E-Class with the OM628 is a rare combination: compact sporting body, massive V8 diesel torque. Less common than the S 400 CDI but the same effortless overtaking promise — without breaking a sweat.
Engine Weaknesses 6
Timing chain stretches from around 150,000 km; chain tensioner and guides wear. Cold-start rattling is a typical early warning. Left untreated, chain jump and total engine failure threaten.
Symptoms: Metallic rattling on cold start that subsides after 3-5 seconds. With severe stretch also audible at operating temperature.
The right turbocharger is the classic weak point of the OM628. Total failure of both turbos from around 90,000-100,000 km has been documented. Repair on the V8 diesel is correspondingly labour-intensive.
Symptoms: Significant power loss, blue or white smoke from exhaust, whistling noise under load.
Under extreme pressure loading, head gaskets fail. CO2 enters the cooling system; increased pressure pushes coolant out through the expansion tank. Engine removal required for repair.
Symptoms: Coolant warning light, coolant overflows from expansion tank, coolant level drops continuously.
Common rail injectors are prone to leaks at copper sealing rings and retaining bolts at high mileages. Injector failure can cause secondary engine damage.
Symptoms: Soot trails, rough running, power loss, fuel smell in engine bay. With advanced damage: starting difficulties.
The rear crankshaft oil seal between engine and gearbox leaks at higher mileages. The gearbox must be removed to replace the seal -- a labour-intensive job.
Symptoms: Oil puddle under vehicle centre to rear, oil film visible between engine and gearbox bell housing.
Recirculated exhaust gases coat the intake manifold, inlet ports and mixing housing with up to 2 cm of soot. Fuel consumption rises measurably; power drops gradually.
Symptoms: Gradual power loss, increased consumption, occasional lurching at part throttle.
Vehicle Weaknesses 6
Sensotronic Brake Control on pre-facelift models (2002–2006) suffered hydraulic failure. Approximately 1.3 million vehicles were recalled worldwide. Repair cost €2,200–3,500.
The Signal Acquisition and Actuation Module (SAM) fails, particularly when water ingress occurs. Leads to loss of lighting, windscreen wipers and instrument cluster.
SBC electrohydraulic brake (2002–2006) suffered from faulty high-pressure pump control. Two recalls in 2004 and 2005. SBC vehicles require specialist workshop.
AIRMATIC air suspension wears heavily. Air reservoir and compressor fail frequently. Replacement requires complete rear axle disassembly — very costly.
Control arm and track rod end bearings develop play. A common MOT failure point. Regular cause for failed MOT inspection.
SAM modules (front and rear) control lighting, wipers and door functions. Moisture damage and ageing lead to complete failures.