Mercedes-Benz AMG GT X290

Return to the inline-six after years of the M276 V6 — and the difference is immediately noticeable. Smoother, more even rev build-up, torque plateau from 1,600–4,000 rpm without any weakness. The 48V mild-hybrid system with integrated starter-generator (ISG) is not a marketing term: 16 kW of boost on pull-away fills turbo lag completely; measurable fuel saving in sail mode. When buying, check the 48V battery — failure costs 2,000–4,000 EUR, primarily affecting build years up to 2022. Electric coolant pumps can fail from 80,000 km. Change oil every 10,000 km, do not rely on Longlife — HPFP and camshaft adjusters are sensitive to old oil. Cold-start wastegate bushing rattle is by design and not a fault. Overall a very accomplished engine that holds 250,000 km without issues when maintained correctly.

• !! 48V ISG Battery Failure from 70,000 km

  Frequently reported problem: 48V battery of the EQ Boost system fails and costs 2,000–4,000 EUR to replace. Design issue with earth connection in early vehicles.

  Symptoms: EQ Boost deactivated, start-stop system failed, hybrid warning light, sporadic starting problems
  2,000–4,000 $
  Ad 48V battery M256EQ Boost battery M256ISG battery M256
• !! Camshaft Adjuster Solenoid Leaking — Oil in Wiring Harness from 100,000 km

  The known Mercedes problem of leaking camshaft solenoids also affects the M256 (same solenoid technology as M276/M270). Oil migrates by capillary action and destroys lambda sensors and the ECU.

  Symptoms: Lambda sensor fault codes, MIL, rough running. Multiple electrical faults simultaneously as it progresses
  1,700–4,000 $
  Ad Oil stop cable M256 camshaft solenoidCamshaft solenoid E450 leakingWiring harness camshaft M256 oil
• !! Elevated Oil Consumption at Higher Mileage from 100,000 km

  M256 shows elevated oil consumption from approx. 100,000 km, attributable to the PCV system and cylinder walls. Regular oil level checks necessary.

  Symptoms: Dropping oil level, occasional bluish smoke after warm-up phase
  500–3,000 $
  Ad Oil consumption M256M256 3.0 turbo oil consumptionPiston rings M256

+ 6 more engine weaknesses + vehicle weaknesses

Return to the inline-six after years of the M276 V6 — and the difference is immediately noticeable. Smoother, more even rev build-up, torque plateau from 1,600–4,000 rpm without any weakness. The 48V mild-hybrid system with integrated starter-generator (ISG) is not a marketing term: 16 kW of boost on pull-away fills turbo lag completely; measurable fuel saving in sail mode. When buying, check the 48V battery — failure costs 2,000–4,000 EUR, primarily affecting build years up to 2022. Electric coolant pumps can fail from 80,000 km. Change oil every 10,000 km, do not rely on Longlife — HPFP and camshaft adjusters are sensitive to old oil. Cold-start wastegate bushing rattle is by design and not a fault. Overall a very accomplished engine that holds 250,000 km without issues when maintained correctly.

• !! 48V ISG Battery Failure from 70,000 km

  Frequently reported problem: 48V battery of the EQ Boost system fails and costs 2,000–4,000 EUR to replace. Design issue with earth connection in early vehicles.

  Symptoms: EQ Boost deactivated, start-stop system failed, hybrid warning light, sporadic starting problems
  2,000–4,000 $
  Ad 48V battery M256EQ Boost battery M256ISG battery M256
• !! Camshaft Adjuster Solenoid Leaking — Oil in Wiring Harness from 100,000 km

  The known Mercedes problem of leaking camshaft solenoids also affects the M256 (same solenoid technology as M276/M270). Oil migrates by capillary action and destroys lambda sensors and the ECU.

  Symptoms: Lambda sensor fault codes, MIL, rough running. Multiple electrical faults simultaneously as it progresses
  1,700–4,000 $
  Ad Oil stop cable M256 camshaft solenoidCamshaft solenoid E450 leakingWiring harness camshaft M256 oil
• !! Elevated Oil Consumption at Higher Mileage from 100,000 km

  M256 shows elevated oil consumption from approx. 100,000 km, attributable to the PCV system and cylinder walls. Regular oil level checks necessary.

  Symptoms: Dropping oil level, occasional bluish smoke after warm-up phase
  500–3,000 $
  Ad Oil consumption M256M256 3.0 turbo oil consumptionPiston rings M256

+ 6 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

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