GLC Generations
| Generation | Years | Engines (US) | Notes |
|---|---|---|---|
| X253 | 2016–2022 | 2.0T I4 (GLC300), 3.0T V6 (GLC43 AMG), 4.0T V8 (GLC63 AMG) | Most common; 4MATIC standard on US models |
| X254 | 2023+ | 2.0T I4 (GLC300), PHEV (GLC350e), 2.0T AMG (GLC43) | New platform; MBUX2 infotainment; plug-in hybrid available |
X253 GLC (2016–2022): What to Know
The X253 GLC300 with the 2.0T four-cylinder and the 9G-Tronic nine-speed transmission is a solid platform. The 2.0T M274 engine in the X253 has seen relatively few endemic failures through 80,000 miles under normal driving conditions. The main service priorities are the 9G-Tronic fluid (40,000-mile interval, no exceptions), spark plugs at 60,000 miles, and the transfer case fluid which Mercedes often omits from dealer-recommended service schedules.
9G-Tronic Transmission Service
The 9G-Tronic (722.9 successor) is mechanically more complex than the 7G-Tronic it replaced. Nine forward gears mean more clutch packs, more solenoids, and more precise hydraulic calibration — all of which degrade if fluid service is deferred. The factory service indicator will tell most GLC300 owners their transmission fluid is fine at 60,000 miles. It isn't. A drain-and-fill with correct Mercedes transmission fluid and a XENTRY adaptation reset at 40,000 miles is the correct interval. The full service procedure and fluid specifications are in the transmission service guide.
Transfer Case Actuator Wear
The 4MATIC all-wheel-drive system on the X253 uses an electronically-actuated transfer case. The actuator motor, which engages and adjusts the AWD torque split, develops wear in the plastic gear teeth over time. Symptoms are a grinding or clunking from the center console area when engaging AWD from a stop, or a 4MATIC fault in the instrument cluster. The actuator replacement is $400–$900 in parts and 2–3 hours of labor. It's not catastrophic but it's an expense worth anticipating on high-mileage X253s.
Panoramic Roof Drain Blockage
The X253 panoramic sunroof option — chosen by the majority of US buyers — has drain tubes routed through the A and C pillars to exit under the car. These drain tubes accumulate debris over time and eventually block, causing water to overflow into the headliner, down the A-pillars, and in some cases onto the cabin floor and electronic modules. Symptoms are musty interior odor, wet carpet in the front footwells, or water staining in the headliner near the sunroof perimeter. Annual drain cleaning is the preventive measure; it takes 30 minutes and costs almost nothing. Neglected drains that overflow can damage COMAND electronics and require significant repair.
Spark Plug Interval on the 2.0T
Mercedes specifies 60,000 miles for spark plug replacement on the M274 2.0T in the GLC300. This is a reasonable interval and reasonably accurate for normal driving. If you use the car predominantly for short trips (under 10 miles per trip) or drive in heavy traffic frequently, 50,000 miles is a more conservative interval. Worn plugs on a direct injection turbocharged engine increase combustion chamber deposits and can cause misfires that store codes without immediately affecting drivability — until they do.
GLC43 AMG Notes
The GLC43 uses the M276 3.0T biturbo V6. Service intervals are tighter: spark plugs at 40,000 miles, oil changes at 5,000-mile maximum intervals with MB 229.51 spec oil, and the same 9G-Tronic service schedule as the GLC300. The M276 is a capable engine that rewards proper maintenance and punishes extended service intervals.
X254 GLC (2023+): New Platform Notes
The X254 is still building a service history track record. Early ownership data suggests the 2.0T M254 engine (new design, replacing M274) is reliable in the first 50,000 miles. The GLC350e plug-in hybrid adds a battery pack and electric motor to the drivetrain — conventional maintenance still applies to all ICE components; the electric elements add brake pad inspection at lower intervals (regenerative braking reduces wear, but dust accumulates differently) and cabin filter changes at the same annual schedule.