Mercedes-Benz AMG C 63 Black Series
6.2-litre naturally aspirated V8, hand-built in Affalterbach to the 'One Man, One Engine' principle. 457–525 hp without any forced induction, rev limit at 7,200 rpm. The sound defines an era: a deep, bass-heavy rumble at 3,000 rpm, a scream above 5,000 that recalls American V8 racing engines. Throttle response is immediate — no turbo lag, no hesitation, every throttle command is executed instantly. Critical issue number one: camshafts wear out through inadequate cold-start lubrication with the factory 0W-40 oil. Switch to Ravenol 5W-40 RCS, let the engine idle for 10 seconds after a cold start, stay below 3,000 rpm until fully warm. Head bolt corrosion on engine numbers below 060658 (up to approx. 2010) — check without fail. Star Technical Bulletin 05.20/20b documents the tappet problem officially. Parts availability is becoming increasingly difficult — hydraulic tappets A1560500225 sometimes not available for months. Maintain the M156 properly and you have one of the most emotional V8s of the last 30 years.
Black Series — 517 hp Racing Car Without Compromise
C63 Black Series: 517 hp, wide arch bodywork, track-tuned suspension from the factory. No rear seat, no comfort options — a racing car that happens to have road registration. The M156 at 6,500 rpm sounds like a NASCAR engine. Fewer than 1,000 units built; appreciation guaranteed.
Engine Weaknesses 10
All M156 up to engine number 060658 affected: head bolts corrode through coolant contact at the bolt head, in worst case break off. Coolant enters the combustion chamber — engine damage. Mercedes fitted improved bolts from approx. 2010 (20x A1560160769 + 4x N000000005754, approx. 108 EUR net). Preventive replacement strongly recommended.
Symptoms: Coolant loss without visible leak, white smoke from exhaust, oil-coolant mixture, check engine light, misfires on individual cylinders.
Main problem of the M156: the factory 0W-40 oil drains from the camshafts at standstill; at cold start the lobes run briefly dry. Wear deteriorates exponentially. Camshaft regrinding (TechnoCam and others) as a cheaper alternative to new parts — 50% saving. Always replace the 32 hydraulic tappets (INA A1560500225) at the same time.
Symptoms: Metallic ticking on cold start that disappears after 30–60 seconds, rough idle, power loss in the upper rev range. Remove valve cover and check lobe tips for wear.
The fit of the locking plate in the camshaft adjuster widens over time — the adjuster slips, timing shifts. Clattering on cold start is the first symptom. Reinforced locking plates (300–1,000 EUR for 4 pieces) as a permanent solution. Bearing cap torque 10 Nm, adjuster 45 Nm + 90°.
Symptoms: Rattling/clattering on cold start for 2–10 seconds, disappears after oil pressure build-up. With advanced wear: also audible when warm, rough idle, shifted timing, power loss.
The plastic timing chain guide rails become brittle over time and can break. Mercedes has developed reinforced replacements. A broken guide rail fragment in the timing drive can cause chain skip and valve damage. Preventive replacement at >100,000 km recommended.
Symptoms: Rattling from the front of the engine that gets louder with rpm, chain tensioner at its stop, check engine light with timing fault codes.
The 32 hydraulic tappets (INA-made, A1560500225) wear alongside the camshafts. Star Bulletin 05.20/20b documents the issue officially. SLS Black Series tappets with improved coating (~35 EUR each vs. 8 EUR each standard) as an upgrade. Parts availability in 2024 was partially unavailable for months.
Symptoms: Metallic ticking/clattering especially on cold start and at idle. Initially only on individual cylinders, then increasingly all. If seized in the head: sudden knocking, valve damage possible.
The factory 0W-40 oil drains completely from the camshafts during standstill. At cold start there is a brief dry-running condition. Switching to Ravenol 5W-40 RCS noticeably resolves this. After cold start, allow 10 seconds idle before revving above 3,000 rpm after reaching operating temperature. Oil consumption of 0.5–1 L/1,000 km with spirited use is normal.
Symptoms: Bluish exhaust smoke after extended standstill on first start, oil level warning with spirited driving, elevated oil consumption especially in summer.
From 80,000–100,000 km the valve stem seals harden and allow oil into the combustion chamber. Typical of high-rpm V8 engines. Repair requires removing the camshafts — worthwhile combined with a camshaft service.
Symptoms: Bluish smoke on throttle application after overrun (traffic light start after downhill), oil consumption rises to >1 L/1,000 km, oil deposits on spark plugs.
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 — cheap wear part, high consequential damage if ignored.
Symptoms: Check engine light, misfires on individual cylinders (felt as hesitation under load), P0300–P0308 fault codes, slight power loss.
The magnesium intake manifold corrodes internally over time — especially on vehicles that sit for long periods. Deposits reduce airflow. Reconditioning the manifold is recommended during a camshaft service. New parts are increasingly difficult to source.
Symptoms: Slight power loss in the upper rev range, visible white corrosion marks on intake manifold removal, rougher throttle response.
The AMG-specific composite brake discs (steel-aluminium compound) last 30,000–50,000 km with spirited use. Replacement considerably more expensive than conventional discs. When buying used: brake condition is a decisive price negotiation point.
Symptoms: Brake disc wear indicator, vibration when braking from high speed, visible grooves and cracks on disc, squealing with cold brakes.
Vehicle Weaknesses 7
Rear subframe rusts from the inside out. Problem not immediately visible externally. In severe cases the rear differential can shift.
Brake lines corrode relatively quickly and are flagged at MOT. Affected two to several times more frequently than the vehicle average.
W204 rear subframes systematically rust through from the inside. Powder coat cracks and moisture penetrates. Mercedes replaces under goodwill (15 years from first registration). In extreme cases the axle breaks.
Brake lines above the rear axle rust through after approximately 8–10 years. Brake fluid loss and brake failure possible. Mercedes goodwill arrangement known up to 8 years.
Pre-facelift models (up to 2011) show clunking front axles from defective shock absorbers, strut top mounts and wishbones. Improved after facelift.
Xenon headlight levelling actuators fail frequently. Error message and dazzling of oncoming traffic.
Shock absorbers and strut mounts of the front axle wear prematurely on the W204. Rumbling and wallowing typical from 100,000 km.
Reports & Tests
4206 owner complaints filed with NHTSA (2007–2014). Most reported: Airbags (1825), Electrical (747), Steering (537).