Mercedes-Benz AMG G 63
5.5-litre V8 BiTurbo — AMG's first forced-induction V8 and the successor to the naturally aspirated M156. 525–585 hp depending on model, up to 900 Nm in the S version. The character is fundamentally different from the M156: instead of a high-revving scream, a brutal torque wave from 1,750 rpm. The sound is deeper, more bass-heavy, with a characteristic turbo hiss on lift-off. Less emotional than the naturally aspirated engine, but in a different league on the motorway — above 200 km/h the M157 still accelerates like others do at 100. Timing chain is the known Achilles heel: chain tensioner failure at 80,000–120,000 km, Mercedes has improved the design (non-return valve in cylinder head oil gallery). Piezo injectors are sensitive to fuel quality, service life 100,000–150,000 km. Turbos last 200,000+ km with proper warm-up and cool-down — shut off immediately after a motorway run and they'll fail significantly earlier. Warm up the engine, allow cool-down after hard use, oil changes every 10,000 km with 0W-40 — then 300,000 km is realistic.
BiTurbo V8 in the G — Big Body, Brutal Punch
G 63 AMG W463 BiTurbo: 544 hp and 760 Nm in the boxiest body in the world. Where the G55 supercharger sounded raw and unrefined, the G63 is a notch more restrained — still a V8, but less rough around the edges. A brutal machine above 60 km/h; via steering wheel paddles one switches between Jekyll and Hyde. 2,550 kg, 5.5 seconds to 100. Fuel consumption 18–22 L/100 km in daily use.
Engine Weaknesses 11
The timing chains on the M157 5.5L BiTurbo V8 stretch, especially on vehicles with frequent cold starts and short trips. Engine damage possible if chain jumps. Extensive repair on the V8.
Symptoms: Metallic rattling on cold start, camshaft position fault codes, rough running, in extreme cases engine damage
Under heavy use the piston rings on the M157 wear prematurely. Oil consumption above 1 L/1,000 km is possible. Engine overhaul required with advanced wear.
Symptoms: Rising oil consumption, blue smoke on acceleration, oil mist from exhaust, oil level warnings
The high-pressure fuel pump on the M157 can wear internally at high mileage. Pressure drop in the rail causes difficult starting and power loss.
Symptoms: Difficult starting, power loss under load, hesitation at high rpm, fuel pressure fault codes
The M157 is affected by known timing chain wear from 80,000–120,000 km. Mercedes retrofitted check valves in the oil supply passages (TSB LI05.20-P-057028).
Symptoms: Rattling on cold start, later also at idle, check engine light with camshaft fault codes, power loss
The oil pump gear on the M157 wears at high rpm and generates metal debris. Oil pressure drop leads to overheating and cylinder bore damage.
Symptoms: Oil pressure warning at high rpm, metallic knocking from lower engine, heavy oil consumption
Timing chain and tensioners wear prematurely, especially model years 2011–2013. Mercedes retrofitted a check valve in the oil passages of the cylinder head. Repair often in the four-figure range, worst case five figures.
Symptoms: Rattling on cold start, later also at idle, increased on acceleration; check engine light
The valve cover gaskets on the M157 V8 leak and allow oil to drip onto the hot turbochargers. Smoke and a burning smell are the result.
Symptoms: Oil smell and smoke from engine bay, oil drops visible on turbochargers, dropping oil level
The M157 uses Bosch piezo injectors that typically last 100,000–150,000 km. Aftermarket alternatives are not available.
Symptoms: Rough engine, uneven idle, elevated fuel consumption, individual cylinder fault codes
Electric auxiliary water pump for charge air cooling fails. Leads to reduced power in limp mode.
Symptoms: Power loss under high load, warning message on display, limp mode
Bosch piezo-ceramic injectors are sensitive to fuel quality and have a limited service life of approx. 100,000–150,000 km. Replacing all 8 injectors costs up to 3,000 EUR; repair is not possible.
Symptoms: Rough running, misfires, power loss, check engine light, poor cold-start behaviour
The wastegate flaps on both turbochargers rattle at cold start due to play in the linkages. Usually an acoustic issue only, rarely performance-related.
Symptoms: Metallic clattering on cold start for 1–2 minutes, disappears at operating temperature
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.