The 2007 Explorer marks the last year of the fourth-gen platform before a major redesign. Both engine options have significant weaknesses: the 4.0L SOHC V6 is known for catastrophic timing chain cassette failures, while the 4.6L V8 suffers spark plug ejection and head gasket issues. Transmission cooler failures are endemic across all configurations.
4.0L SOHC Timing Chain Cassette Failure
Common · high severityTypical onset: 100,000-150,000 mi
Symptoms: Rattling noise on cold start that disappears after warm-up, Check engine light with cam/crank correlation codes, Sudden catastrophic engine failure with metal shavings in oil, Loss of power or rough running
Fix: The plastic timing chain cassettes disintegrate, sending debris through the engine. By the time symptoms appear, internal damage is often done. Requires complete timing chain replacement with updated metal guides (8-12 hours labor), but many engines need full rebuilds or replacement due to bearing/cylinder damage from debris. This is THE killer for the 4.0L SOHC.
Estimated cost: $2,500-$8,000
Transmission Oil Cooler Line Failure and Cross-Contamination
Common · high severityTypical onset: 80,000-130,000 mi
Symptoms: Transmission fluid in coolant (strawberry milkshake appearance), Engine coolant in transmission, Transmission slipping or erratic shifting, Overheating transmission or engine
Fix: The internal transmission cooler inside the radiator develops leaks, allowing coolant and ATF to mix. This destroys both the transmission and can damage the engine. Requires radiator replacement, complete transmission flush and filter (sometimes full transmission replacement if damage occurred), coolant system flush, and all cooler lines (6-10 hours labor if caught early, 15-25 hours if transmission is damaged).
Estimated cost: $1,200-$5,500
4.6L V8 Spark Plug Ejection and Thread Damage
Occasional · high severityTypical onset: 60,000-120,000 mi
Symptoms: Sudden loud popping or hissing sound from engine, Misfire on one cylinder, Loss of compression on affected cylinder, Spark plug blows out of head entirely
Fix: The 2-valve 4.6L has insufficient thread engagement for spark plugs, and they can strip out or eject completely under combustion pressure. Time-Sert or Helicoil thread repair is possible if caught early (3-5 hours per plug), but often requires cylinder head removal for proper repair (8-12 hours). Using factory torque specs and anti-seize is critical during plug changes.
Estimated cost: $800-$3,000
Rear Axle Seal and Bearing Failure
Occasional · medium severityTypical onset: 90,000-140,000 mi
Symptoms: Gear oil leaking from rear wheel area, Howling or grinding noise from rear axle during acceleration, Vibration at highway speeds, Clunking when changing from forward to reverse
Fix: Rear axle seals leak, contaminate brakes, and if ignored lead to bearing failure. Seal replacement is straightforward (2-3 hours per side), but bearing failure requires axle shaft replacement and sometimes differential work (5-8 hours). The 8.8-inch rear end is robust, but maintenance matters.
Estimated cost: $400-$1,800
Lower Control Arm Ball Joint Failure
Common · medium severityTypical onset: 70,000-110,000 mi
Symptoms: Clunking over bumps from front end, Wandering or loose steering feel, Uneven tire wear on inside edge, Visible play when prying on tire at 6 and 12 o'clock
Fix: The ball joints are pressed into the lower control arms and wear out. Ford doesn't sell ball joints separately, so you're replacing entire control arms. Front alignment required after replacement (3-4 hours labor for both sides plus alignment).
Estimated cost: $600-$1,000
Overhead Console and Rear Liftgate Release Switch Failure
Occasional · low severitySymptoms: Overhead compass/temperature display blank or garbled, Rear liftgate won't release from interior button, Dome lights intermittent or stuck on, HomeLink garage opener stops working
Fix: The overhead console module fails due to poor solder joints on the circuit board. The liftgate release switch also commonly fails. Console replacement or repair (1 hour labor), switch replacement is separate (0.5 hour). Annoyance factor high, but not a breakdown issue.
Estimated cost: $200-$500
Hard pass on the 4.0L V6 unless timing chains are proven done; the 4.6L V8 is marginally better but still a money pit after 100k miles — better options exist in this price range.
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.