Mercedes-Benz SLS AMG
6.2-litre naturally aspirated V8 with dry-sump lubrication — a development of the M156 with forged crankshaft, lighter pistons and hand-polished intake manifold. 571 hp at 6,800 rpm without any forced induction. The sound is pure muscle-car V8: a deep rumble at 3,000 rpm, a scream above 5,000 that recalls Le Mans. Throttle response is immediate — no turbo lag, no delay, every command executed instantly. Technically significantly more mature than the M156: the critical head bolts were improved from the factory, the dry sump eliminates oil starvation in corners. The tappets remain the biggest residual risk as a legacy from the M156 — thermal overloading of the front cylinders under aggressive driving. Oil changes every 10,000 km with 10W-60 are non-negotiable. Service A every 15,000 km, Service B every 30,000 km. One of the most reliable AMG powerplants ever — most problems come from sitting unused, not from driving.
Gullwings, 571 hp NA, No Turbo — Pure Madness
The SLS is not a car, it's an experience. Open the gullwing doors, start the V8, the growl fills the garage. 571 hp naturally aspirated with dry sump — throttle response like a light switch. Only 7,000 coupés built, every one a future classic. Sensationally balanced on country roads despite the long wheelbase. Anyone who has felt the throttle response at 5,000 rpm understands why turbo fans get jealous.
Engine Weaknesses 9
The hydraulic tappets on the front cylinders (1–4) overheat under aggressive use and can seize in the cylinder head. The SLS Black Series had modified tappets as a factory fix. Symptom: metallic ticking after hot driving, in worst case valve damage.
Symptoms: Metallic ticking/clattering after hot driving or track use, initially only audible when cold, then permanent. Power loss if valve no longer closes correctly.
Inherited from the M156: head bolts corrode through coolant contact and can break in worst case. Mercedes switched to improved bolts in 2010. On the SLS (from 2010) improved from the factory — only affects the very first 2010 production batch.
Symptoms: Coolant loss without visible leak, white smoke from exhaust, oil-coolant mixing, overheating warning.
Under sustained high-rpm use individual valve springs can break — consequential damage up to engine failure. Extremely rare on the M159 (rarer than on the M156), but documented as a residual risk on track cars with >100,000 km.
Symptoms: Sudden metallic bang, immediate power loss, check engine light. With a broken valve: engine runs extremely rough or not at all.
The camshaft adjusters lose oil pressure over time and rattle at cold start for 2–5 seconds. A known issue from the M156, less common on the M159 due to better oil supply. With prolonged operation without repair: shifted timing, power loss.
Symptoms: Rattling/chainsaw noise on cold start for 2–5 seconds, disappears after oil pressure build-up. With deterioration: also audible when warm, rough idle.
The M159 consumes noticeably more oil with sporty use and high oil temperatures than under normal operation. The dry-sump has a large oil capacity (9L) but on track days consumption can rise to 1–1.5 L/1,000 km. 10W-60 is the mandatory oil grade.
Symptoms: Oil level warning after track use, bluish exhaust smoke at high load after extended standstill, oil consumption >1 L/1,000 km with aggressive driving.
Under sustained load on track the M159 enters limp mode when oil temperature exceeds 150°C. Not a fault but a protection function — frustrating on track days. Oil cooler upgrade from Weistec or RENNtech resolves the issue.
Symptoms: Sudden power drop on track after 3–5 fast laps, oil temperature warning in instrument cluster, engine limits rpm to 4,500.
The 8 individual ignition coils are wear items and fail sporadically from 60,000 km. If ignored, catalytic converter damage from unburnt fuel is a risk. Always replace all 8 at the same time.
Symptoms: Check engine light, misfires on individual cylinders, slight hesitation under load, P0300–P0308 fault codes.
The Getrag 7-speed DCT shows shift delays and judder when manoeuvring at low speed. Software update (2012) significantly improves the issue. Change DCT oil every 40,000 km. Gearbox replacement on total failure costs over 12,000 EUR.
Symptoms: Judder on pull-away and manoeuvring, 1–2 second shift delay during gear changes in town, occasional crunch when downshifting quickly.
The optional composite ceramic brakes last considerably longer than steel brakes (60,000–100,000 km) but cost over 15,000 EUR to replace. Steel brake discs are a cheaper alternative. Significantly faster wear with track day use.
Symptoms: Brake disc wear indicator, squealing at low temperatures (normal for ceramic), visible grooves and chipping on the disc.
Vehicle Weaknesses 6
The Getrag DCT wears above average with frequent urban use and slip-start pull-aways. Gearbox overhaul at Mercedes is very costly.
The optional carbon-ceramic brake system can be worn out after as little as 15,000-20,000 km, particularly with sporting use. In wet conditions, there is delayed brake response followed by abrupt bite.
The gas struts and hinges of the gullwing doors lose strength over time. Doors open more slowly or no longer stay up.
The aluminium front wishbones show premature bush wear with sporting driving. Rumbling over bumps.
The optional carbon-ceramic brake system wears above average with frequent everyday use with cold brakes. Disc replacement is extremely expensive.
A wiring fault at the oil pressure sensors was documented on early SLS AMG vehicles. The cable routing is not adequately rated.
Reports & Tests
15 owner complaints filed with NHTSA (2010–2015). Most reported: Airbags (11), Fuel System (2), Cruise Control (1).