Mercedes-Benz G 300 TD
Inline-six diesel, partly with turbocharging. Very solid engine with high refinement. Injection pump can cause problems with age.
Off-Road Workhorse of the Old School
The old diesel in the G — reliable, frugal, and with genuine off-road character. Not driving pleasure in the conventional sense.
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 7
The W463 rusts structurally at window frames (not painted inside from the factory), lower door edges and sills. This problem runs through all model years up to 2018.
The steel ladder frame corrodes at spring seats and cross-members. The double-shell construction is insufficiently sealed and traps moisture.
Window frames are not painted on the inside from the factory and rust heavily. Tailgate and frame sections rust due to missing factory treatment. Full rust treatment up to 7,600 EUR.
Shock absorbers, springs and track rod ends wear out prematurely due to off-road use and the vehicle's high weight.
Worm gear in the steering box shows highest wear in the straight-ahead position. Steering levers and track rod ends are disproportionately often flagged at inspection.
ECU failures often only fixable by complete replacement. Older vehicles with moisture in the engine bay particularly affected. Specialist workshops offer cheaper repair options.
Moisture frequently enters headlights and tail lights, causing short circuits and bulb failures. Tail lights with poor factory sealing are particularly affected.