Mercedes-Benz SLK R171

Compact four-cylinder with mechanical supercharger. Known for timing chain stretch from approx. 100,000 km. Supercharger magnetic clutch can fail. Manual gearbox rare.

• !! Timing Chain Stretches Prematurely from 85,000 km

  The simplex timing chain on the M271 is the most well-known wear issue: it can stretch before 100,000 km. In advanced stages it skips teeth and causes engine damage.

  Symptoms: Rattling on cold start (diesel-like noise), camshaft fault codes, check engine light, in extreme cases engine damage
  800–2,500 $
  Ad Timing chain M271Timing chain kit M271Chain tensioner M271Camshaft adjuster M271
• !! Camshaft Adjuster Leaks — Oil in Wiring Harness from 120,000 km

  The camshaft adjuster solenoids develop leaks. The wiring harness absorbs oil by capillary action, which migrates as far as the engine ECU and damages it.

  Symptoms: CEL with P0010/P0015, oil traces at camshaft connectors, in worst case ECU failure
  80–1,800 $
  Ad solenoid valve camshaftnversteller M271Öl-Stopp-Kabel A2711502733camshaftnverstellermagnet 2710500647
• !! Camshaft Adjuster Leaks Oil into Connector from 100,000 km

  The camshaft adjuster seals on the M271 become porous and allow oil into the electrical connectors. The result is fault codes and check engine light.

  Symptoms: Check engine light, camshaft adjuster fault codes, rough running, oil in adjuster connector
  200–600 $
  Ad Camshaft adjuster M271Camshaft adjuster seal M271VVT solenoid M271

+ 3 more engine weaknesses + vehicle weaknesses

Four-valve V6 with variable valve timing. Smooth and powerful. Known for balance shaft wear (revision sprocket) on early build years. Balance shaft gear problem addressed by Mercedes with a recall.

• !! Balance Shaft Sprocket Wears Prematurely from 140,000 km

  The plastic balance shaft sprocket on the M272 wears prematurely from the timing chain. The right cylinder bank goes out of timing. Affected up to end of October 2006.

  Symptoms: Fault codes P0016/P0017 (camshaft right bank), chain rattling, rough running at idle, in extreme cases engine damage
  2,500–5,500 $
  Ad Balance shaft M272Balance shaft sprocket M272 V6A2720500747 balance shaft sprocket
• !! Timing Chain Stretches and Damages Timing from 120,000 km

  Alongside the balance shaft issue the M272 shows premature timing chain stretch. Chain wear on softer sprockets leads to timing deviations.

  Symptoms: Chain noise especially on cold start, camshaft fault codes, rough running, engine irregularities
  2,000–4,000 $
  Ad Timing chain M272 V6Timing chain kit M272Chain guide M272
• !! Camshaft Adjuster Leaks — Wiring Harness Contaminated from 90,000 km

  Four camshaft adjuster solenoids (two per cylinder bank) develop leaks; oil creeps into the wiring harness as far as the ECU. Repair costs up to €1,700 documented.

  Symptoms: CEL, oil traces at camshaft connectors, lambda sensor failure due to oil contamination, non-specific faults that recur
  100–1,700 $
  Ad solenoid valve camshaftnversteller M272Zentralventil M272 A2720500578Zentralventil A2720500478

+ 3 more engine weaknesses + vehicle weaknesses

Four-valve V6 with variable valve timing. Smooth and powerful. Known for balance shaft wear (revision sprocket) on early build years. Balance shaft gear problem addressed by Mercedes with a recall.

• !! Balance Shaft Sprocket Wears Prematurely from 140,000 km

  The plastic balance shaft sprocket on the M272 wears prematurely from the timing chain. The right cylinder bank goes out of timing. Affected up to end of October 2006.

  Symptoms: Fault codes P0016/P0017 (camshaft right bank), chain rattling, rough running at idle, in extreme cases engine damage
  2,500–5,500 $
  Ad Balance shaft M272Balance shaft sprocket M272 V6A2720500747 balance shaft sprocket
• !! Timing Chain Stretches and Damages Timing from 120,000 km

  Alongside the balance shaft issue the M272 shows premature timing chain stretch. Chain wear on softer sprockets leads to timing deviations.

  Symptoms: Chain noise especially on cold start, camshaft fault codes, rough running, engine irregularities
  2,000–4,000 $
  Ad Timing chain M272 V6Timing chain kit M272Chain guide M272
• !! Camshaft Adjuster Leaks — Wiring Harness Contaminated from 90,000 km

  Four camshaft adjuster solenoids (two per cylinder bank) develop leaks; oil creeps into the wiring harness as far as the ECU. Repair costs up to €1,700 documented.

  Symptoms: CEL, oil traces at camshaft connectors, lambda sensor failure due to oil contamination, non-specific faults that recur
  100–1,700 $
  Ad solenoid valve camshaftnversteller M272Zentralventil M272 A2720500578Zentralventil A2720500478

+ 3 more engine weaknesses + vehicle weaknesses

Naturally aspirated V8 in three displacements from 4.3 to 5.5 litres — old-school character with no turbo lag. Linear power delivery, deep rumble from 2,000 rpm building to a hoarse roar above 5,000. Peak torque at 3,000; beyond that it thins out — yet it's silky in part-throttle and surprisingly economical. Achilles heel is the seals: rear crankshaft oil seal practically universal above 150,000 km (gearbox removal required, 600–900 EUR), valve covers and oil filter housing seep with age. All cheap parts. The one critical point: the rubber damper on the crankshaft pulley hardens with age — when it fails the pulley machines into the sump. Replace preventively every 150,000 km. Oil changes every 10,000 km with 5W-40, 16 spark plugs every 60,000–80,000 km — then 400,000 km is realistic.

• !! Vibration Damper/Pulley — Rubber Hardens from 170,000 km

  The rubber damper in the crankshaft pulley hardens with age and can eat into the sump — catastrophic consequential damage. Preventive replacement every 150,000 km strongly recommended.

  Symptoms: Unusual vibrations at idle, in worst case metallic scraping from below. Often no prior warning — sudden failure.
  400–2,000 $
  Ad Vibration damper pulley M113Crankshaft pulley rubber damper M112 M113
• !! Rear Crankshaft Seal Leaking from 150,000 km

  The rear crankshaft seal is leaking on virtually all M113 engines above 150,000 km. Gearbox removal required — 600–900 EUR workshop costs. If oil creeps into the torque converter it becomes expensive.

  Symptoms: Oil drops or oil film visible at the engine-gearbox interface, oil loss without any other apparent leak on the engine.
  600–900 $
  Ad A1129970246 crankshaft seal M113Crankshaft seal M113 rear
• !! Engine Mounts Worn Prematurely from 90,000 km

  Engine mounts can fail before 100,000 km. Practical test: finger between the stabiliser bar and front sump — no clearance means the mount is dead. Not visually checkable without removal.

  Symptoms: Vibrations in interior especially at idle, dull rumbling on acceleration, in worst case contact between engine and bodywork.
  200–500 $
  Ad Engine mount M113 W211Engine mount M113 W220

+ 7 more engine weaknesses + vehicle weaknesses