Mercedes-Benz G 350 Turbo D
Inline-six diesel with pre-chamber or swirl-chamber injection. Turbocharged version powerful for the era. Solid long-distance runners.
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 6
The hydraulic chain tensioner wears at high mileage. A stretched timing chain can skip at high rpm, causing valve-to-piston contact.
Symptoms: Rattling from the timing chain area on cold start, metallic clacking, rough engine running
The vacuum pump bearing wears and fails. Released bearing balls can get between the timing chain and sprocket, causing catastrophic engine damage.
Symptoms: Reduced brake feel (hard pedal), weak servo assistance, sudden metallic noises
A leaking radial shaft seal on the vacuum pump lets oil into the vacuum circuit. Result: brake booster works unreliably — safety relevant!
Symptoms: Brakes sporadically feel hard with no servo assistance, increased pedal travel, oil traces on vacuum line, inconsistent braking effect
The OM603 has a well-known head gasket weakness between the first cylinder and the oil passage to the timing chain. The newer Elring gasket 835.730 includes a metal reinforcement at this location.
Symptoms: Oil film in coolant reservoir, coolant loss without visible external leak, air bubbles in expansion tank under acceleration
On the OM603, oil cooler gaskets can develop leaks at high mileage, especially on the turbo variant due to higher thermal loads.
Symptoms: Milky oil colour on dipstick, grey streaks in coolant reservoir, unexplained oil loss, elevated coolant temperature
The heavier OM603 six-cylinder loads the engine mounts more than the four-cylinder. Vibrations at idle and during load changes are typical.
Symptoms: Heavy droning and vibrations at idle, engine rocks visibly during load changes, knocking noises on start-up
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.