Mercedes-Benz AMG S 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.
585 hp BiTurbo open-top — ultimate touring drop-top
S 63 AMG Cabriolet A217: 585 hp with the roof down — the M157 sounds deep and present with the roof open, BiTurbo sound right around the ears. 2.2 tonnes are honestly perceptible, but long-distance comfort is unmatched. Not a sports car, but the ultimate touring cabriolet with a V8 heart. Soft-top quality first-class; wind protection usable to 200 km/h.
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 17
The active electro-hydraulic ABC suspension requires intensive maintenance. Hydraulic lines, valve blocks and pumps can develop leaks. Hydraulic oil change required every 50,000 km.
Air bags and pressure hoses develop leaks. The compressor runs continuously and overheats. Repair: air bag pair 2,500–3,500 €, compressor 1,000–1,300 €.
The tension and pull cables of the soft-top headliner snap, preventing the roof from folding and closing correctly. Affects A217, A205 and A238 in the same way.
Soft-top actuation hydraulic cylinders develop leaks through heat and seal ageing. Hydraulic oil drips onto seats or collects in the roof compartment.
Air struts on Airmatic and Magic Body Control suspensions develop leaks. Vehicle drops, suspension warning light appears. Repair per corner is very costly.
The hydraulic Magic Body Control suspension is prone to valve block and hydraulic pump failures. Contamination in the oil causes system failures.
The COMAND infotainment system freezes sporadically or fails completely. System faults increase from around 100,000 km.
Radar and camera sensors for adaptive cruise control and emergency braking can cause malfunctions due to dirt or defects. Calibration after repair is expensive.
The COMAND navigation system shows read errors, freezes or fails to boot. A defective drive unit is the most common cause.
Matrix LED headlights are not repairable -- individual modules cannot be replaced. Moisture and electronic failures require complete headlight replacement.
Window regulators fail or become unresponsive. Cause is often a software fault in the door control unit, fixable by update.
Brake discs and pads wear quickly due to the high vehicle weight. Particularly during spirited driving.
Frameless door windows are inherently harder to seal. Worn seals or minimal window misalignment cause wind whistling from around 80 km/h.
The pneumatic control unit operates soft-close, central locking and rear headrests via a shared pump. Leaks cause all functions to fail simultaneously.
The Comand NTG5 infotainment system shows display failures, freezing and navigation start errors. Temperature-dependent malfunctions occur frequently.
Seat heating mats and massage pneumatics in the multicontour seats are wear items. Heating mats fail internally, the PSE pump loses pressure for the massage function.
The rubber seal of the Keyless Go microswitch in door handles becomes brittle through UV and temperature cycling. Moisture enters, the switch corrodes.