Mercedes-Benz G-Klasse W463a

Modern inline-six diesel with aluminium block and steel pistons. Efficient and powerful, few known weaknesses to date. Timing chain long-lived.

• !! Recall Coolant Pump — Fire Hazard (Action Code 2090008)

  The vacuum-controlled coolant pump can develop leaks between the coolant and vacuum circuits. Coolant enters the EGR solenoid valves; an electrochemical reaction creates a fire hazard.

  0–0 $
  Ad coolant pump OM656Unterdruckventil OM656Aktionscode 2090008
• !! Bosch CP4 Pump Sensitive to Fuel Quality from 120,000 km

  The Bosch CP4 high-pressure pump is more sensitive to fuel contamination than its predecessors. Poor diesel quality can damage the pump and injectors.

  Symptoms: Power loss, hesitation, injection system fault codes, in severe cases engine damage from metal swarf
  1,500–6,000 $
  Ad high-pressure fuel pump OM656Bosch CP4-high-pressure fuel pump OM656fuel filter OM656
• !! Coolant Pump Leaking — Fire Risk (Recall) from 50,000 km

  The switchable coolant pump does not reliably seal between the coolant and vacuum circuits. Coolant can overheat electrical solenoid valves — fire risk. Campaign code 2090008.

  Symptoms: No direct driver symptoms — preventive recall. Possible coolant loss, electrical faults, unusual odour
  0–0 $
  Ad Coolant Pump OM656 A6560900564Solenoid Valve Coolant Recall 2090008Vacuum Valve Coolant Pump W223

+ 3 more engine weaknesses + vehicle weaknesses

Modern inline-six diesel with aluminium block and steel pistons. Efficient and powerful, few known weaknesses to date. Timing chain long-lived.

• !! Recall Coolant Pump — Fire Hazard (Action Code 2090008)

  The vacuum-controlled coolant pump can develop leaks between the coolant and vacuum circuits. Coolant enters the EGR solenoid valves; an electrochemical reaction creates a fire hazard.

  0–0 $
  Ad coolant pump OM656Unterdruckventil OM656Aktionscode 2090008
• !! Bosch CP4 Pump Sensitive to Fuel Quality from 120,000 km

  The Bosch CP4 high-pressure pump is more sensitive to fuel contamination than its predecessors. Poor diesel quality can damage the pump and injectors.

  Symptoms: Power loss, hesitation, injection system fault codes, in severe cases engine damage from metal swarf
  1,500–6,000 $
  Ad high-pressure fuel pump OM656Bosch CP4-high-pressure fuel pump OM656fuel filter OM656
• !! Coolant Pump Leaking — Fire Risk (Recall) from 50,000 km

  The switchable coolant pump does not reliably seal between the coolant and vacuum circuits. Coolant can overheat electrical solenoid valves — fire risk. Campaign code 2090008.

  Symptoms: No direct driver symptoms — preventive recall. Possible coolant loss, electrical faults, unusual odour
  0–0 $
  Ad Coolant Pump OM656 A6560900564Solenoid Valve Coolant Recall 2090008Vacuum Valve Coolant Pump W223

+ 3 more engine weaknesses + vehicle weaknesses

Modern inline-six diesel with aluminium block and steel pistons. Efficient and powerful, few known weaknesses to date. Timing chain long-lived.

• !! Recall Coolant Pump — Fire Hazard (Action Code 2090008)

  The vacuum-controlled coolant pump can develop leaks between the coolant and vacuum circuits. Coolant enters the EGR solenoid valves; an electrochemical reaction creates a fire hazard.

  0–0 $
  Ad coolant pump OM656Unterdruckventil OM656Aktionscode 2090008
• !! Bosch CP4 Pump Sensitive to Fuel Quality from 120,000 km

  The Bosch CP4 high-pressure pump is more sensitive to fuel contamination than its predecessors. Poor diesel quality can damage the pump and injectors.

  Symptoms: Power loss, hesitation, injection system fault codes, in severe cases engine damage from metal swarf
  1,500–6,000 $
  Ad high-pressure fuel pump OM656Bosch CP4-high-pressure fuel pump OM656fuel filter OM656
• !! Coolant Pump Leaking — Fire Risk (Recall) from 50,000 km

  The switchable coolant pump does not reliably seal between the coolant and vacuum circuits. Coolant can overheat electrical solenoid valves — fire risk. Campaign code 2090008.

  Symptoms: No direct driver symptoms — preventive recall. Possible coolant loss, electrical faults, unusual odour
  0–0 $
  Ad Coolant Pump OM656 A6560900564Solenoid Valve Coolant Recall 2090008Vacuum Valve Coolant Pump W223

+ 3 more engine weaknesses + vehicle weaknesses

The M177 is AMG's most widely used V8 biturbo today and is considered technically mature and long-lived. The hot-V turbocharger arrangement delivers spontaneous response with barely perceptible lag. Weaknesses are manageable: wastegate rattle in cold weather, ignition coil recall for early 2015 model years, valve cover gaskets with age. Regular oil changes with attention to oil quality deliver a very robust engine. In direct comparison with the M156 less emotional, but significantly more reliable and efficient.

• !! MCT Gearbox — Clutch Wears in City Traffic from 60,000 km

  The MCT Speedshift gearbox (wet launch clutch instead of torque converter) wears the clutch significantly faster in frequent stop-and-go. Clutch replacement requires gearbox removal.

  Symptoms: Judder on pull-away, clutch slip at full load, gearbox warning message, delayed engagement from standstill
  3,000–6,000 $
  Ad MCT clutch AMG C63 W205Speedshift MCT clutch kitA2052500200 MCT clutch
• !! Camshaft Adjuster Solenoid Draws Oil into Wiring Harness from 70,000 km

  Identical issue to the M176/M278: the solenoid leaks, oil migrates by capillary action through the wiring harness. On AMG vehicles this is even more frequent due to higher oil temperatures.

  Symptoms: Cold-start rattle, camshaft adjuster fault code, oil traces on connector, potential ECU consequential damage
  500–3,000 $
  Ad Camshaft adjuster M177 AMGOil stop ring M177 wiring harnessA1779050100 solenoid
• !! Camshaft Cover Gasket Leaking — Hot-V Area from 60,000 km

  The camshaft cover gaskets on the M177 AMG V8 become brittle from the high heat exposure in the hot-V. Oil escapes onto turbochargers and exhaust system.

  Symptoms: Oil smell on hot engine, oil film on turbochargers, smoke from engine bay
  800–2,500 $
  Ad Camshaft cover gasket M177Valve cover gasket AMG 4.0 V8

+ 5 more engine weaknesses + vehicle weaknesses

4.0-litre V8 with two turbochargers in the cylinder valley — the so-called hot-inside-V arrangement keeps the exhaust paths short and virtually eliminates turbo lag. The M176 is the civilian variant of the AMG V8: same basic architecture, different mapping, not a hand-built individual unit. Water-cooled charge air coolers in the cylinder valley reduce intake charge temperature from over 140°C to near ambient. Cylinder deactivation silences four cylinders at part-load — only perceptible as minimal steering wheel vibration. Maintenance note: do not push oil change intervals, as the oil separator in the crankcase breather reacts badly to old oil and, when blocked, pushes out the valve cover gasket — extensive front-end disassembly required. Change spark plugs every 80,000 km, plan intake valve carbon cleaning after 70,000 km. When buying used, listen for wastegate rattle at part-load — addressable via Xentry. Check camshaft adjuster solenoids for oil traces at the connector.

• !! Timing Chain Stretch — M176 4.0L V8 from 120,000 km

  The timing chains on the M176 V8 can stretch at high mileage. Due to the hot-inside-V design the repair is very complex as the turbochargers sit between the cylinder banks.

  Symptoms: Chain rattling on cold start, camshaft fault codes, rough idle
  4,000–10,000 $
  Ad Timing chain M176Chain tensioner 4.0 V8 BiTurbo
• !! Camshaft Adjuster Solenoid Draws Oil into Wiring Harness from 80,000 km

  The camshaft adjuster solenoid on the M176 leaks and oil migrates by capillary action through the wiring harness to the ECU. A known Mercedes V8 issue since the M278.

  Symptoms: Cold-start rattle for 1–2 seconds, camshaft adjuster fault code, oil traces on connector, in extreme cases ECU failure
  400–2,500 $
  Ad Camshaft adjuster M176 solenoidOil stop ring M176 wiring harnessA2769050200 camshaft solenoid
• !! Coolant Pump Leaking from 80,000 km

  The coolant pump on the M176 can develop a leak at the seal. Coolant loss leads to engine overheating if not addressed.

  Symptoms: Coolant level drops, coolant puddle under the vehicle, temperature gauge rises
  400–1,200 $
  Ad Coolant pump M176Water pump M176 4.0 V8

+ 6 more engine weaknesses + vehicle weaknesses