The 2015 E-350 with the 6.8L V10 Triton is a workhorse van that suffers from well-documented spark plug ejection issues and transmission cooler failures. When maintained properly it can reach high mileage, but the engine's fundamental design flaw and trans cooler weakness make these expensive gambles in the used market.
Spark Plug Ejection / Stripped Threads (Triton V10)
Common · high severityTypical onset: 60,000-150,000 mi
Symptoms: Sudden misfire with loud popping or hissing from engine bay, Check engine light with cylinder-specific misfire codes, Loss of power, rough idle, Sometimes catastrophic — plug shoots out completely
Fix: The 2-piece spark plug design and inadequate thread engagement in the aluminum head cause plugs to strip threads or eject. Requires HeliCoil or TimeSert thread repair per cylinder (2-3 hours labor each), sometimes multiple cylinders. Severe cases need head removal and machining. Prevention: replace plugs every 30k-40k miles, never when engine is hot, use anti-seize sparingly.
Estimated cost: $800-1,500 per cylinder for in-chassis repair, $4,000-7,000+ if head removal required
Transmission Oil Cooler Failure
Common · high severityTypical onset: 80,000-140,000 mi
Symptoms: Transmission fluid in coolant (strawberry milkshake in overflow tank), Coolant in transmission (slipping, erratic shifts, fluid looks pink/foamy on dipstick), Overheating of transmission or engine, Loss of forward gears if contamination is severe
Fix: Factory cooler inside the radiator develops internal leak, mixing ATF and coolant. Requires radiator replacement, full transmission flush (sometimes multiple flushes), cooler line replacement, often external auxiliary cooler addition. If caught late, transmission rebuild needed due to coolant contamination destroying clutches. 6-8 hours labor for cooler/flush, add 15-25 hours if trans needs rebuild.
Estimated cost: $1,200-2,000 for cooler/radiator/flush if caught early, $4,500-7,500 if transmission rebuild required
Exhaust Manifold Studs Breaking / Leaks
Common · medium severityTypical onset: 70,000-120,000 mi
Symptoms: Loud ticking or tapping from engine, worse on cold start, Exhaust smell in cabin, Visible soot streaks on manifold or head, Check engine light (O2 sensor codes from exhaust leak)
Fix: Manifold studs break due to heat cycling, letting manifolds crack or leak at the flange. Removing broken studs from aluminum heads is time-intensive; often requires drilling and extraction. 4-6 hours per side, both sides commonly affected. Aftermarket stud kits (not OEM bolts) are the fix.
Estimated cost: $1,200-2,200 per side depending on stud extraction difficulty
Fuel Pump Driver Module Failure
Occasional · high severityTypical onset: 90,000-150,000 mi
Symptoms: No-start, cranks but won't fire, Intermittent stalling, especially when hot, Loss of fuel pressure, No fuel pump priming sound when key turned on
Fix: The fuel pump driver module (FPDM) mounted on the frame rail fails due to heat and corrosion. It's a separate module from the PCM that controls pump speed. Diagnosis requires checking for power/ground and command signal. Replacement is straightforward once located — 1-1.5 hours labor. Module costs $150-300.
Estimated cost: $350-550
Transmission Mount Failure
Common · low severityTypical onset: 80,000-130,000 mi
Symptoms: Clunk or thud when shifting into drive or reverse, Vibration at idle in gear, Excessive driveline movement felt through floor, Visible sag or cracking in rubber mount
Fix: The rear transmission mount deteriorates from engine torque and weight. Inspection from underneath shows torn rubber or collapsed mount. Replacement is simple — 1-1.5 hours labor. Often done alongside engine mounts if they're also worn.
Estimated cost: $250-450
Intake Manifold Runner Control Sticking
Occasional · low severityTypical onset: 100,000-160,000 mi
Symptoms: Check engine light with P2004/P2005/P2006 codes (IMRC stuck), Slight power loss at low RPM, Rough idle, Carbon buildup visible in throttle body
Fix: The intake manifold runner control flaps stick due to carbon buildup on shafts. Requires intake manifold removal, cleaning, and sometimes replacement if bushings are worn. 4-5 hours labor. Can sometimes be cleaned in place with heavy-duty throttle body cleaner if caught early.
Estimated cost: $600-1,200 depending on whether cleaning or replacement needed
Buy only if priced $3,000-5,000 below market to cover inevitable spark plug thread repairs and trans cooler replacement — otherwise you're inheriting someone else's deferred time bomb.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.