Mercedes-Benz AMG SL 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 4MATIC roadster — BiTurbo in any weather
SL 63 AMG R231 with 4MATIC: 585 hp distributed to all four wheels. The safer choice in wet conditions and winter use, slightly less playful than the rear-wheel-drive version on dry tarmac. The Vario-roof makes it suitable year-round. The R231 is stiffer and more direct than the R230 — the most composed SL ever for long motorway journeys.
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 8
Leaking front ABC dampers were documented on early R231 examples. A new damper from Mercedes costs 1,900 EUR; reconditioned units are available for half the price.
The ABC hydraulic oil absorbs moisture. The pH drops, rubber components dissolve and contaminate valves and lines. Annual change is mandatory.
Active Body Control loses hydraulic pressure through non-use or ageing. Valves become coated with deposits, pressure accumulators lose membrane tension. Regular Pentosin change every 50,000 km is essential.
The folding roof can develop leaks through aged seals, particularly at the side guides and in the A-pillar area.
High quiescent current draw. Battery discharges quickly with prolonged standstill. AGM battery must be maintained regularly.
Pressure lines are partly routed incorrectly from the factory and become porous through pinching. Hydraulic oil escapes and the roof stops in any position.
The vario roof develops creaking, rattling or clicking noises. Recalibration by the dealer eliminates the noises. Cost approximately 540 EUR.
The bonding of the roof seal at the transition to the windscreen detaches with age. Water runs along the A-pillar into the interior.
Reports & Tests
35 owner complaints filed with NHTSA (2012–2020). Most reported: Engine (7), Powertrain (7), Wheels (7).