Mercedes-Benz AMG GT 53
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.
GT 53 — Almost a Proper AMG
435 hp EQ Boost, 0–100 in 4.5 seconds — the GT 53 is measurably quick. The inline-six runs smoothly, the chassis is firm and sporting. What's missing: the V8 pulse of the GT 63. At £40,000 less than the GT 63, a sensible compromise — though nobody buys this car for sensibility. Convincing on long distances nonetheless.
Engine Weaknesses 9
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
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
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
The beltless M256 operates exclusively electric coolant pumps. Pump motors fail internally and trigger temperature warnings. Bleeding requires specialist diagnostic equipment.
Symptoms: Coolant temperature warning, irregular operating temperature, occasional overheating warning
The camshaft-driven high-pressure pump on the M256 can wear prematurely with irregular oil changes. Injectors can be damaged by metal debris.
Symptoms: Fuel pressure fault codes, rough idle, starting problems, hesitation under load, elevated fuel consumption
With predominantly short-trip use the OPF cannot fully regenerate. Power drop and elevated consumption result. Virtually no risk for motorway drivers.
Symptoms: Power drop at higher load, elevated fuel consumption, occasional particulate filter warning, engine runs rougher
The M256 uses Camtronic variable valve actuation — same technology as M276/M270 with documented failures. Wear on the adjustment unit or solenoid valve is possible. Oil quality is decisive.
Symptoms: Hesitation at low rpm, camshaft position sensor fault code, rough idle, engine warning with power reduction
Direct injection on the M256 inline-six causes carbon deposits on intake valves. Walnut blasting every 60,000–80,000 km recommended.
Symptoms: Hesitation in the lower rev range, rough idle, sporadic misfires on cold start
Rattling on cold start from the wastegate guide bush with design-inherent play. BorgWarner states this is necessary so the wastegate does not stick at operating temperature. Mercedes classes it as state of the art — not a defect.
Symptoms: Rattling or clattering in the first seconds after cold start, disappears after warm-up
Vehicle Weaknesses 6
Some X290 owners reported sudden vehicle shutdown caused by the AMG Speedshift MCT abruptly engaging neutral. Gearbox software update required.
After software updates, engine control units were permanently damaged on some X290 units. One owner reported 14 days in the workshop and a complete replacement of instrument cluster and ECUs.
Mercedes recalled 12,509 AMG GT models (X290) worldwide. The processor in the high-voltage starter-generator ECU can overload and shut down the drivetrain system.
Multiple documented software faults in the MBUX system: complete instrument cluster failure, Distronic and active brake assist non-functional, rear spoiler unresponsive.
The 8-speed DCT shows harsh gear changes when upshifting from 1st to 2nd in comfort mode. Software updates do not always resolve the problem completely.
The MBUX infotainment system freezes after OTA updates or loses functions such as voice control, navigation and traffic sign recognition. Cause: incompatibilities between new software and existing hardware.