Mercedes-Benz AMG GT 63 S
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.
639 hp four-door — strongest M177 with rear seats
The maximum M177 power in a four-door car. 639 hp push the X290 to 100 in 3.2 seconds. Drift mode standard — then pure rear-wheel drive with over 600 hp. In daily use GT-comfortable, on track surprisingly agile for 2.1 tonnes. Centre armrest roller rattles, rear seat equipment disappoints despite the price. One early owner after quality issues: Would I order it again? Probably not.
Engine Weaknesses 8
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
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
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
The M177 has several electric auxiliary coolant pumps for charge air cooling. These fail and lead to elevated charge air temperatures with power reduction.
Symptoms: Power reduction during spirited driving, cooling system fault codes, elevated charge air temperature
The camshaft adjuster solenoids on the M177 can leak internally or stick. Fault codes for camshaft position and rough running are the result.
Symptoms: Check engine light, rough idle, camshaft position fault codes, power loss in the lower rev range
Vehicles with M177/M178 engines built between Jan. and Nov. 2015 had faulty ignition coils that caused misfires. Mercedes replaced affected parts under a recall.
Symptoms: Rough idle, misfires, check engine light, occasional limp mode
The wastegate flaps of the BiTurbo system clatter briefly after cold start. Normally disappears after a few seconds. With prolonged operation replace the wastegate actuator.
Symptoms: Metallic clattering directly after cold start, disappears after warm-up, permanent with wear
As a direct-injection engine without port injection, carbon residues build up on the intake valves. Walnut blasting every 50,000–80,000 km recommended. Performance loss is gradual.
Symptoms: Gradually roughening idle, slight power loss, elevated fuel consumption
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.