2021 MERCEDES-BENZ GLA250 H247

Typical onset: 40,000-80,000 mi

Symptoms: Severe knocking or rattling from engine bay, especially under load, Metal shavings in oil during changes, Sudden loss of oil pressure warning, Check engine light with misfire codes or low oil pressure, Catastrophic failure can occur without warning

Fix: Complete engine rebuild or short block replacement required. M260 engines in this generation have documented piston ring land failures and bearing wear issues leading to spinning bearings and crankshaft damage. Dealership typically recommends whole engine assembly. Expect 18-25 labor hours for short block swap, more for full rebuild with machine work.

Estimated cost: $12,000-22,000

Typical onset: 50,000-90,000 mi

Symptoms: Transmission fluid leaking near front of vehicle, Transmission running hot, harsh shifting when warm, Pink/red fluid dripping from radiator area, Limp mode activation on highway drives

Fix: The 8-speed dual-clutch transmission uses an integrated cooler that develops leaks at crimp joints or internal fractures. Requires cooler replacement and full fluid flush. Not a DIY-friendly job due to specialized fill procedure and programming requirements. 3-4 labor hours.

Estimated cost: $1,200-1,800

Typical onset: 35,000-70,000 mi

Symptoms: Clunking when shifting from Park to Drive or Reverse, Excessive vibration at idle in Drive, Visible sag or cracking in rubber mount, Rattling over bumps at low speed

Fix: The hydraulic transmission mount fails prematurely on H247 platform, likely due to undersizing for the dual-clutch unit's characteristics. Replacement is straightforward but requires supporting the transmission. 1.5-2 labor hours.

Estimated cost: $450-700

Typical onset: 60,000-100,000 mi

Symptoms: Rough idle and hesitation during acceleration, Extended cranking before start, especially when hot, Check engine light with fuel pressure fault codes (P0087, P0088), Limp mode under hard acceleration

Fix: M260 direct-injection system is sensitive to fuel quality. Filter clogs prematurely with poor fuel; high-pressure pump cam follower wears causing pressure loss. Pump is engine-mounted, requires partial intake removal. Filter replacement alone: 1 hour. Pump replacement: 4-5 hours.

Estimated cost: $800-2,200

Typical onset: 70,000-110,000 mi

Symptoms: White smoke from exhaust on cold start, Coolant loss with no visible external leaks, Overheating episodes without obvious cause, Oil contamination with milky appearance, Bubbling in coolant reservoir at idle

Fix: Though listed as 'both' in repair frequency (carryover nomenclature from V-config engines), the I4 M260 can suffer head gasket failure from repeated overheating or improper torque on previous repairs. Requires cylinder head removal, machining check, new gasket, and timing component inspection. 10-14 labor hours.

Estimated cost: $3,500-5,500