The 2019 AMG GT with its hand-built M177/M178 4.0L twin-turbo V8 is a high-strung performance car that demands meticulous maintenance. Early examples have shown catastrophic engine failures due to oiling issues and rod bearing wear, while transmission cooler leaks and software glitches are common annoyances.
Connecting Rod Bearing Failure (M177/M178 Engine)
Occasional · high severityTypical onset: 30,000-60,000 mi
Symptoms: Metallic knocking noise from engine bay, especially cold start or under load, Oil pressure fluctuations or warning light, Metal shavings in oil filter during routine oil change, Sudden catastrophic failure with complete engine seizure
Fix: This is the nightmare scenario: requires complete engine-out teardown, crankshaft inspection/grinding, new bearings, often new pistons and rings. If rods are scored, you're looking at short block replacement or full rebuild. 40-60 hours labor depending on damage extent. Mercedes extended warranty to 10yr/120k mi on some VINs but not all 2019s qualify.
Estimated cost: $15,000-35,000
Transmission Oil Cooler Leak
Common · medium severityTypical onset: 40,000-80,000 mi
Symptoms: Transmission fluid puddle under car, driver side front area, Burnt transmission fluid smell after spirited driving, Transmission temperature warning on dash, Harsh shifting or delayed engagement when fluid level drops
Fix: The DCT cooler lines and cooler itself crack from heat cycling. Requires front undertray removal, draining trans fluid, replacing cooler assembly and lines. 4-6 hours labor, plus factory DCT fluid refill and adaptation procedure with XENTRY diagnostics.
Estimated cost: $1,800-2,800
Transmission Mount Failure
Common · medium severityTypical onset: 50,000-90,000 mi
Symptoms: Loud clunk when shifting from Park to Drive or Reverse, Vibration through cabin at idle or during aggressive acceleration, Visible transmission sag when inspecting from underneath, Knocking noise over bumps from driveline area
Fix: The rear transmission mount (hydraulic type) tears internally from the DCT's violent shifts. Requires lifting transmission slightly with jack, removing old mount, pressing in new OEM unit. 3-4 hours labor. Aftermarket units exist but OEM recommended for proper NVH control.
Estimated cost: $1,200-1,800
Fuel Filter/High Pressure Fuel Pump Contamination
Occasional · high severitySymptoms: Sudden loss of power, limp mode activation, Check engine light with fuel pressure fault codes (P0087, P0088), Rough idle or misfires under boost, Long crank time or no-start condition
Fix: The high-pressure direct injection system is sensitive to fuel contamination. Fuel filter located in tank requires tank drop. If pump is contaminated, both pumps (low and high pressure) plus injectors may need cleaning or replacement. Tank drop and reinstall 6-8 hours, plus injector service if needed. Always use Top Tier fuel.
Estimated cost: $2,000-5,000
Head Gasket Failure (Overheating-Related)
Rare · high severityTypical onset: 60,000-100,000 mi
Symptoms: White smoke from exhaust on cold start, Coolant loss with no visible leaks, Oil milky/frothy on dipstick or oil cap, Rough idle and misfires, coolant smell from exhaust
Fix: Usually follows overheating event (track use, coolant leak ignored). Requires engine-out service, heads removed and resurfaced, new gaskets, ARP studs recommended. Check for warped heads. 50-70 hours labor. If cylinder walls are scored, you're into short block territory.
Estimated cost: $12,000-18,000
Electrical System Software Glitches (NHTSA Recalls)
Occasional · low severitySymptoms: Infotainment system freezes or reboots randomly, Transmission fault messages with no actual mechanical issue, Intermittent loss of parking sensors or camera, Battery drain from modules not sleeping properly
Fix: Multiple NHTSA recalls for software updates to transmission control unit and body control modules. Dealer-only fix via XENTRY flash, 1-2 hours. Check if your VIN has open recalls. Independent shops cannot perform Mercedes software updates without dealer-level access.
Estimated cost: $0-300
Buy one only if you have deep pockets and access to a Mercedes specialist—when they run, they're intoxicating, but the M177/M178 engine reliability issues make this a high-risk used purchase without warranty coverage.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.