Mercedes-Benz G 320
Inline-six with four-valve technology. Solid, long-lived engine with good refinement. Keep to regular cambelt change intervals.
G-Class, As Is
G-Class with 155 kW — the experience comes from the vehicle, not the engine.
Engine Weaknesses 7
The M104 head gasket fails at high mileage. Coolant enters the cylinders or the oil. Repair requires removing the head and resurfacing.
Symptoms: Coolant loss without visible leak, white exhaust plume, mayonnaise on oil cap, rising coolant temperature
The hydraulic chain tensioner on the M104 leaks oil at the timing chain housing. The leak causes oil loss and can cause chain rattling if it fails.
Symptoms: Oil spot at front of engine, brief rattling after cold start, dropping oil level
The M104 inline-six carries a conventional ignition distributor on the exhaust camshaft. Cap and rotor wear out, cracks in the distributor cap cause arcing in wet conditions.
Symptoms: Stumbling under load, misfires in wet conditions, poor cold-start behaviour, rough idle at cold start
The KE-Jetronic fuel injection of early M104 variants (300E, 300CE) suffers from ageing of the fuel distributor and electro-hydraulic pressure regulator. Replacement parts are barely available.
Symptoms: Poor warm-start behaviour, rough running above 80°C coolant temperature, over-rich mixture, sooty spark plugs
The M104 hydraulic lifters lose oil pressure during extended standstill and clatter after cold start. Usually gone after 30–60 seconds; with persistent clattering replacement is needed.
Symptoms: Ticking clatter directly after engine start, disappears after warm-up, permanently audible when worn
The valve cover gasket on the M104 inline-six hardens with age and starts leaking. Oil drips onto the exhaust manifold causing smoke. Simple repair.
Symptoms: Oil smell from engine bay, smoke on hot engine, oil spots on side of engine
The crankcase ventilation rubber hoses on the M104 harden after 20–30 years and crack. False air enters the intake tract, oil mist contaminates the throttle body.
Symptoms: Rough idle, oil deposits on throttle body, increased oil consumption, oil pushed out of the dipstick tube when the system is blocked
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.