Mercedes-Benz AMG GLC 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.
510 hp compact SUV — Nürburgring record holder among SUVs
7:49 on the Nürburgring Nordschleife at launch — SUV record. 510 hp, rear axle lock standard after facelift, air suspension plus adaptive dampers. The S model gives the GLC the necessary bite — where the base 63 stays comfortable, the S pushes without compromise. 14.9 L in tests, real-world 15–17 L. From €130,000 post-facelift. There will be no V8 successor — the new GLC63 has a four-cylinder.
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 11
Aluminium steering rack bolts corrode due to road salt. If all three bolts fracture, power steering fails completely. KBA recall 012425.
Panoramic roof can spontaneously shatter while driving, triggered by temperature differentials or pre-damaged surfaces. Glass shards inside the cabin. No systematic recall known.
Recall in late 2021 due to fire risk from possible fuel leak. Affects GLC models build years 2015–2020. Free repair by dealer.
The 9-speed automatic jerks when changing gear, particularly between low gears. Defective wiring harnesses can cause drive loss. A software update often helps.
Active brake assist, ESP and blind-spot monitor fail sporadically. Corroded wiring harnesses and control unit faults are the causes.
AMG models with large wheels tend to develop noises at the front axle when turning on wet roads. Ball joints and strut top mounts wear faster.
The rear brakes wear unusually quickly due to frequent ESP interventions. First warnings can appear as early as 35,000–40,000 km.
The Artico synthetic leather on GLC seats cracks on many vehicles after just 3–5 years. Replacement cost per seat is €500–800.
The Artico synthetic leather on seats and door cards cracks and flakes prematurely, particularly at the side bolsters.
Many GLC owners report persistent brake squeal that does not disappear even after pad replacement. AMG models with sports pads are frequently affected.
The standard Artico artificial leather shows cracks from approx. 40,000 km, particularly on the side bolsters and backrest of the driver's seat. Mercedes occasionally offers goodwill repair.
Reports & Tests
538 owner complaints filed with NHTSA (2015–2022). Most reported: Engine (158), Other (99), Electrical (79).