Mercedes-Benz E 300 D
Inline-six diesel, partly with turbocharging. Very solid engine with high refinement. Injection pump can cause problems with age.
Diesel Standard
100 kW diesel. Functional and economical, devoid of emotion.
Engine Weaknesses 7
The OM606 is considered extremely robust, but the timing chain can stretch from around 400,000 km. With turbo conversion and increased sustained load, this occurs earlier.
Symptoms: Rattling from the timing chain area on cold start, starting difficulties with heavily stretched chain
The OM606 is more robust than the OM603, but head gasket damage occurs on overheating or at extreme mileage. When the head needs to be resurfaced, costs rise significantly.
Symptoms: Coolant loss, white smoke from exhaust, oil film in expansion tank, engine overheats sporadically, power loss
The OM606 LA (turbo) uses vacuum boost pressure control, which develops leaks with age. Replacement turbocharger approximately €650 (aftermarket), original Mercedes approximately €1,900.
Symptoms: Power loss under load, whistling from turbocharger, blue smoke at full load, boost pressure gauge reading erratic
On the OM606, oil cooler gaskets can develop leaks with age, especially on the turbo engine due to thermal stress. Installation is complex due to the hard-to-reach position.
Symptoms: Oil streaks in coolant, milky-brown engine oil, unexplained coolant loss, elevated engine temperature
Like the OM604 and OM605, the OM606 suffers from the intake valve stem elongation issue. BGA repair tappets (approximately €10 each, 1 mm shorter) allow a cost-effective repair.
Symptoms: Difficult cold starting, engine starts only on 2nd–3rd attempt, rough running until operating temperature, quiet ticking in valvetrain
The Bosch inline injection pump shows ageing of seals and line connections. Fuel at line connections and pump housing is typical from 200,000 km.
Symptoms: Fuel smell after switching off, visible dampness on pump housing
The OM606 is the heaviest of the classic Mercedes inline diesel engines. Engine mounts wear correspondingly earlier. Lemförder or Corteco approximately €50 per unit.
Symptoms: Vibrations and droning in the cabin at idle, engine rocking when starting and stopping, clunking during load changes
Vehicle Weaknesses 6
Bacterial contamination in the electrophoretic coating bath compromised paint adhesion. Rust appears on doors, roof, boot lid and trim strips. Mercedes offered goodwill repairs.
Strut towers corrode severely and can break away from the bodywork. Safety-critical defect: the vehicle can drop uncontrollably.
Wheel arches, sills and strut towers rust heavily. Hidden rust forms beneath the sill cladding.
Front and rear strut towers rust through. At the front the towers can break while driving. At the rear this is an economic write-off.
Electronic ignition lock wears out over time. Key turns but vehicle won't start. Problems worsen in cold weather.
Typical electrical problems: alarm system triggers false alerts, cruise control cuts out, air conditioning shows faults. Cable oxidation is frequently the cause.