2016 GMC SAVANA

Typical onset: 80,000-150,000 mi

Symptoms: Ticking or tapping noise from engine at idle that worsens when warm, Check engine light with P0300-series misfire codes or P0171/P0174 lean codes, Sudden loss of power or rough running on specific cylinders, Metal shavings in oil during changes (catastrophic failure in progress)

Fix: AFM system uses collapsible lifters that fail, dropping valve springs or sending debris through the engine. Early catch means lifter replacement, camshaft inspection, and AFM delete (~18-24 hours labor). Late catch means full engine rebuild or replacement with all pistons, bearings, crank polishing, and machine work (~35-50 hours). Many techs now recommend preemptive AFM delete tuning on high-mileage units.

Estimated cost: $3,500-12,000

Typical onset: 70,000-120,000 mi

Symptoms: Transmission fluid leaking near radiator or along frame rails, Transmission overheating warnings or limp mode under load, Pink or milky transmission fluid (indicates coolant contamination), Harsh or delayed shifts when towing or loaded

Fix: The 6L80/6L90 transmission cooler lines rust through or the cooler itself clogs with debris, especially on vans used for towing or frequent short trips. Requires cooler line replacement, external cooler flush or replacement, and full transmission fluid flush. If coolant mixed into trans, expect internal damage requiring rebuild (~22-28 hours total). Upgrading to aftermarket heavy-duty cooler recommended.

Estimated cost: $800-4,500

Typical onset: 60,000-100,000 mi

Symptoms: Loud ticking or exhaust leak noise from engine bay, especially on cold start, Exhaust smell in cabin or around vehicle, Loss of low-end torque or slight fuel economy drop, Visible soot streaks on manifold or head

Fix: The 6.0L exhaust manifold bolts corrode and snap, or manifolds crack at the ports. Passenger side is worse due to heat. Requires manifold removal, drilling out broken studs, re-tapping, and new manifold gaskets (~6-9 hours per side). Many techs use stainless studs and high-temp anti-seize on reinstall. If both sides fail simultaneously, budget for both.

Estimated cost: $900-1,800

Typical onset: 90,000-140,000 mi

Symptoms: No-start or extended cranking, especially when hot, Intermittent stalling at idle or during acceleration, Loss of power under load or uphill, Whining noise from fuel tank area

Fix: In-tank fuel pump fails or pressure regulator diaphragm ruptures, dumping fuel pressure. Requires dropping the 31-gallon midship tank (~3-4 hours labor), pump module replacement, and fuel filter change. Van configuration makes tank access labor-intensive. Many techs also replace fuel filter housing if it shows corrosion.

Estimated cost: $800-1,400

Typical onset: 70,000-110,000 mi

Symptoms: Loud clunk when shifting from park to drive or reverse, Vibration through floor at idle in gear, Excessive driveline movement visible when accelerating or braking, Transmission housing contacting crossmember (audible bang)

Fix: The rubber transmission mount deteriorates from heat and load cycles, allowing excessive driveline movement. Common on vans that idle extensively or tow heavy. Requires trans mount replacement and crossmember inspection for damage (~1.5-2.5 hours). Check engine mounts simultaneously as they often fail together.

Estimated cost: $250-500

Typical onset: 80,000-130,000 mi

Symptoms: Check engine light with P0449, P0455, or P0442 EVAP codes, Difficulty fueling (pump clicks off repeatedly), Fuel smell near vehicle or inside cabin, Rough idle when fuel tank is full

Fix: EVAP vent valve on top of fuel tank or purge solenoid on engine fails, causing emissions system leaks. Vent valve requires tank drop (3-4 hours labor bundled with other tank work), purge solenoid is accessible from engine bay (~0.8-1.2 hours). Many techs smoke-test entire system to rule out rusted vent lines.

Estimated cost: $300-900