2015 FORD E-350

Typical 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

Typical 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

Typical 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

Typical 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

Typical 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

Typical 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