2014 GMC YUKON XL 2500

Typical onset: 80,000-150,000 mi

Symptoms: Check engine light with P0300-series misfire codes, Ticking or tapping noise from valve train, especially on cold start, Rough idle, Loss of power under load

Fix: Active Fuel Management lifters collapse due to oil starvation or debris, causing cam lobe wear. Repair requires both heads off, cam replacement, all 16 lifters, new AFM valley cover, and often AFM delete kit to prevent recurrence. 16-20 labor hours if no machine work needed.

Estimated cost: $3,500-6,000

Typical onset: 100,000-180,000 mi

Symptoms: Burning 1+ quart every 500-1,000 miles, Blue smoke on startup or acceleration, Fouled spark plugs, Oil pressure fluctuations

Fix: Ring land carbon buildup and ring flutter on AFM-equipped engines cause blow-by. Many owners run it until rings completely fail. Proper fix is engine-out rebuild or short block replacement—20-26 labor hours including R&R and assembly.

Estimated cost: $5,500-9,000

Typical onset: 70,000-130,000 mi

Symptoms: Transmission fluid pooling under vehicle near radiator, Low transmission fluid warnings, Pink residue at radiator connection points, Slipping or delayed shifts if fluid level drops

Fix: Factory crimp-style cooler lines corrode at fittings or crack from vibration. Replace both lines, not just the leaker. Some shops also replace the in-radiator cooler if contamination suspected. 2-3 labor hours, flush required.

Estimated cost: $400-800

Typical onset: 90,000-140,000 mi

Symptoms: Clunk when shifting into Drive or Reverse, Vibration at idle in gear, Visible transmission sag or excessive movement, Driveline shudder on acceleration

Fix: Rubber mount separates from bracket due to torque and heat. Requires jack support of transmission and crossmember removal. 1.5-2 labor hours.

Estimated cost: $250-450

Typical onset: 100,000-160,000 mi

Symptoms: Hard starting after sitting, Intermittent stalling or hesitation under load, Whining noise from fuel tank area, Check engine light with lean codes (P0171/P0174)

Fix: In-tank pump module wears out; filter sock clogs with sediment. Requires tank drop on XL models due to length. Replace entire module, not just pump. 2.5-3.5 labor hours depending on tank fuel level and corrosion.

Estimated cost: $600-1,100

Typical onset: 120,000-200,000 mi

Symptoms: White smoke from exhaust, Coolant loss with no visible leaks, Overheating, Milky oil on dipstick or cap, Combustion gases in coolant (test with block tester)

Fix: Usually occurs after repeated overheating or detonation from neglected maintenance. Both heads off, resurface if warped, new gaskets, ARP studs recommended. 12-16 labor hours plus machine shop time.

Estimated cost: $2,800-4,500