Mercedes-Benz CL C216

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.

• !! Timing Chain Stretch — M157 BiTurbo V8 from 100,000 km

  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
  3,000–8,000 $
  Ad Timing chain M157Chain tensioner AMG 5.5 BiTurbo
• !! Oil Consumption from Piston Ring Wear from 120,000 km

  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
  4,000–10,000 $
  Ad Piston rings M157Pistons AMG 5.5 BiTurbo
• !! High-Pressure Fuel Pump Fails — No Fuel Pressure from 100,000 km

  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
  1,200–3,000 $
  Ad High-pressure pump M157HPFP AMG 5.5 BiTurbo

+ 8 more engine weaknesses + vehicle weaknesses

Large-displacement naturally aspirated V8, second generation with variable valve timing on all four camshafts. Technically related to the M272 V6 — shares its known balance shaft sprocket problem on build years before 2007 (engine number below 088611). From that number the sprocket was made of hardened steel. Check early engines for fault codes P0016/P0017 and cold-start chain noise. The 5.5-litre with 285 kW is the typical variant; the 5.0-litre with 225–250 kW is somewhat more forgiving in heavier vehicles. The M278 BiTurbo successor is more efficient and more powerful, but sounds considerably less characterful — the M273 is the last true naturally aspirated V8 from Stuttgart. Pre-purchase: always check for camshaft adjuster leaks (oil in wiring harness) and thermostat fault P0128. Oil changes every 10,000 km with MB 229.5.

• !! Balance shaft sprocket — same weakness as M272 from 140,000 km

  The M273 V8 shares the balance shaft sprocket issue with the M272 V6. The soft composite material of the sprocket wears down, causing timing chain rattle.

  Symptoms: Fault codes P0016/P0017, chain rattling, rough idle, power loss
  2,500–5,500 $
  Ad Ausgleichswelle M273 V8Ausgleichswellen-Umlenkrad M273Ausgleichswelle M273
• !! Camshaft Adjuster Leaking — Oil in Wiring Harness from 110,000 km

  As with the similarly-designed M272, the solenoid valves leak. The V8 has 4 per bank — consequential costs are particularly high due to more solenoids. Oil migrates by capillary action all the way to the ECU.

  Symptoms: Check engine light with camshaft fault codes P0014/P0015/P0021/P0025, lambda sensor failures, in extreme cases ECU failure
  200–2,000 $
  Ad Solenoid camshaft adjuster M273Centre valve M273 V8Oil stop cable V8 Mercedes
• !! Valve cover gaskets leaking on both sides from 130,000 km

  Like the M113, the valve cover gaskets on the M273 V8 become porous over time. With a V8 having two cylinder heads, the workload doubles.

  Symptoms: Oil spots under the vehicle, oil smell after hard driving, oily engine bay
  400–1,000 $
  Ad valve cover gasket M273 V8valve cover gasket M273Elring M273

+ 6 more engine weaknesses + vehicle weaknesses

Twelve cylinders, two turbochargers, a V-valley layout — technically fascinating and maintenance-intensive in equal measure. The fully encapsulated ignition module system with two banks at 1,400 EUR each is the most well-known cost factor; failure of both banks usually follows in quick succession. The oil-water heat exchanger in the V-valley almost always leaks eventually — factor in engine removal for the repair. The four camshaft solenoids fail to seal reliably after 80,000–100,000 km; oil creeps into the wiring harness and corrodes control units. Both turbochargers sit deep under the engine bay — removal and installation costs more than the turbo itself. Runs without issue beyond 300,000 km with diligent maintenance; what kills it is deferred servicing. Purchase requirement: complete service history, documented wiring harness check, no ABC alarm backlog, fresh ignition modules.

• !! Ignition module bank failure (two banks at ~€1,400 each) from 120,000 km

  Both ignition module banks are fully potted wear items with a typical service life of 10–15 years. Failures tend to follow each other quickly. OEM cost approximately €1,400 each.

  Symptoms: Jerking and power loss, rough running, misfire codes P0307–P0312, petrol smell from the exhaust
  1,400–3,500 $
  Ad M275 ignition moduleM275 ignition coil pack
• !! Turbocharger wear and wastegate wear from 180,000 km

  The two turbochargers show bearing and wastegate wear at high mileage. Engine removal is required for replacement; repair costs €2,000–4,000 per turbo.

  Symptoms: Whistling or rattling turbo noises, power loss under hard acceleration, blue smoke from oil loss
  2,000–8,000 $
  Ad M275 turbochargerturbocharger M275 V12
• !! ABC hydraulic lines and engine mounts — double defect from 100,000 km

  The M275 V12 Biturbo in the S600/CL600 puts extreme stress on the engine mounts due to its weight (>300 kg engine). At the same time, the ABC hydraulic lines age and leak. Both issues frequently occur together.

  Symptoms: ABC suspension hydraulic oil loss, engine sitting lower, vibrations in the cabin, ABC warning message
  2,000–5,000 $
  Ad engine mount M275 V12 W221ABC Hydraulikleitung S600A2212800175 engine mount V12

+ 6 more engine weaknesses + vehicle weaknesses

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.

• !! Head Bolt Corrosion — Coolant in Combustion Chamber from 50,000 km

  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.
  1,500–8,000 $
  Ad Head bolt M156A1560160769 head boltN000000005754
• !! Camshaft Wear — Cold-Start Lubrication Deficit from 60,000 km

  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.
  2,000–6,000 $
  Ad Camshaft M156A1560504301 inlet camshaftA1560500225 hydraulic tappet INACamshaft regrind M156
• !! Camshaft Adjuster — Locking Plate Wears Out from 70,000 km

  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.
  800–3,000 $
  Ad Camshaft adjuster M156Locking plate M156 reinforcedCamshaft adjuster repair kit AMG

+ 7 more engine weaknesses + vehicle weaknesses

Twelve cylinders, two turbochargers, a V-valley layout — technically fascinating and maintenance-intensive in equal measure. The fully encapsulated ignition module system with two banks at 1,400 EUR each is the most well-known cost factor; failure of both banks usually follows in quick succession. The oil-water heat exchanger in the V-valley almost always leaks eventually — factor in engine removal for the repair. The four camshaft solenoids fail to seal reliably after 80,000–100,000 km; oil creeps into the wiring harness and corrodes control units. Both turbochargers sit deep under the engine bay — removal and installation costs more than the turbo itself. Runs without issue beyond 300,000 km with diligent maintenance; what kills it is deferred servicing. Purchase requirement: complete service history, documented wiring harness check, no ABC alarm backlog, fresh ignition modules.

• !! Ignition module bank failure (two banks at ~€1,400 each) from 120,000 km

  Both ignition module banks are fully potted wear items with a typical service life of 10–15 years. Failures tend to follow each other quickly. OEM cost approximately €1,400 each.

  Symptoms: Jerking and power loss, rough running, misfire codes P0307–P0312, petrol smell from the exhaust
  1,400–3,500 $
  Ad M275 ignition moduleM275 ignition coil pack
• !! Turbocharger wear and wastegate wear from 180,000 km

  The two turbochargers show bearing and wastegate wear at high mileage. Engine removal is required for replacement; repair costs €2,000–4,000 per turbo.

  Symptoms: Whistling or rattling turbo noises, power loss under hard acceleration, blue smoke from oil loss
  2,000–8,000 $
  Ad M275 turbochargerturbocharger M275 V12
• !! ABC hydraulic lines and engine mounts — double defect from 100,000 km

  The M275 V12 Biturbo in the S600/CL600 puts extreme stress on the engine mounts due to its weight (>300 kg engine). At the same time, the ABC hydraulic lines age and leak. Both issues frequently occur together.

  Symptoms: ABC suspension hydraulic oil loss, engine sitting lower, vibrations in the cabin, ABC warning message
  2,000–5,000 $
  Ad engine mount M275 V12 W221ABC Hydraulikleitung S600A2212800175 engine mount V12

+ 6 more engine weaknesses + vehicle weaknesses