2004 Ford Explorer Problems: 11 Known Issues

On the 2000-2010 Ford Explorer 4.0L SOHC V6, the 4.0L SOHC Cologne V6 is notorious for timing chain guide and cassette failures, especially the rear cassette that is difficult to access with the engine installed. Plastic guide material breaks down over time, causing startup rattle, persistent chain noise, cam timing errors, and eventually severe engine damage if the chain jumps timing. This is one of the best-known Explorer engine problems of the era and is documented across owner forums, repair databases, and NHTSA complaints.

On the 2002-2005 Ford Explorer 4.6L V8, the optional 4.6L 2-valve modular V8 (shared with the Mercury Mountaineer) has aluminum heads that engage only a few spark-plug threads (~0.25 in). Under thermal cycling the plug can strip the threads and eject from the head, sometimes blowing out the coil boot with it. Ford acknowledged the stripped/missing-thread condition in TSB 07-21-2 for 1997-2008 4.6/5.4/6.8L 2V engines. Ejection causes a loud pop, sudden misfire and power loss, and a fuel-vapor fire risk.

On the 2002-2005 Ford Explorer, on the 2002-2005 independent-rear-suspension Explorer/Mountaineer the rear coil springs corrode and snap into pieces, sometimes with almost no off-road use, pointing to a manufacturing/coating defect. A broken spring drops that corner with a loud bang, and the fractured end can migrate outward and puncture the adjacent rear tire — a serious safety concern that generated dozens of CarComplaints reports. Especially prevalent in road-salt regions.

On the 2002-2010 Ford Explorer, the independent front suspension on the 2002-2010 Explorer/Mountaineer uses upper control arms with pressed-in ball joints that wear out relatively early. Worn upper (and lower) ball joints produce a clunk over bumps, vague/loose steering, and cupped or inner-edge tire wear. On these stamped-steel upper arms the ball joint is a press fit, and owners frequently report it will not stay seated once worn, so the practical fix is often the complete control arm.

On the 2002-2010 Ford Explorer, a very common failure on third- and fourth-generation Explorers with the 5R55W/5R55S automatic is wear in the overdrive and intermediate servo bores inside the transmission case. As the bores wear, hydraulic pressure leaks past the servo pistons, leading to 1-2, 2-3 and 4-5 flare, slipping, harsh engagement, and delayed or missing reverse. This issue is widely documented in owner complaints, transmission repair communities, and Ford service literature addressing shift flare and servo-related repairs.

On the 2002-2005 Ford Explorer, the 2002-2005 Explorer/Mountaineer instrument panel cluster (IPC) suffers internal failures that cause fluttering, sticking or dead gauges — speedometer, tachometer, fuel and temperature — plus dim/dead odometer segments. Ford issued a Special Service Message noting some 2002-2003 clusters lock up from an internal fault. Corroded cluster connector pins and cold-solder joints on the circuit board are typical culprits, making it a frequent 'gauges dead' search.

On the 1995-2010 Ford Explorer, the cable-drive window regulators on the Explorer/Mountaineer/Sport Trac fail as their plastic cable guides crack and the steel lift cable frays or jumps off the drum. The window then binds, drops crooked, or falls down inside the door — the motor often still runs. The front door regulators are the most common, and the original glass/regulator is riveted, complicating the repair. A very high-frequency 'window fell down' search across the whole 1994-2010 range.

On the 1997-2004 Ford Explorer, on 4.0L Explorers (both the OHV Cologne and the later SOHC V6) P1506 is a common high-idle complaint on higher-mileage trucks. The idle air control valve sits on the throttle body and meters bypass air around the closed throttle plate. Crankcase vapour routed through the PCV system, plus normal intake carbon, gradually coats the IAC pintle and its seat. The pintle stops seating fully, so even when the PCM commands the valve to its minimum duty cycle, more air keeps bleeding past than the strategy allows. The PCM compares commanded position against actual RPM, sees idle running above the target, and stores P1506. The second pattern on this platform, and the one that catches people who have already thrown an IAC at the truck, is an EVAP canister purge valve stuck partly open. The purge valve is plumbed into intake vacuum downstream of the throttle plate, so a leaking purge solenoid is functionally an uncommanded vacuum leak the IAC cannot compensate for. Ford's diagnostic material for P1506 lists the EVAP purge system among the causes, and Explorer owners repeatedly report replacing the IAC, clearing the code, and having it return until the purge valve is addressed. Owners describe a cold-start flare that will not come down until the transmission is put in gear, a hanging idle on deceleration, an idle that stays elevated when warm, and a slight lurch when shifting into drive. Fuel economy drops and the truck can creep against the brakes at a stop.

On the 2002-2005 Ford Explorer, third-generation Explorers are well known for cracking in the rear liftgate applique panel beneath the glass, often around the Ford emblem area, and for corrosion at the liftgate glass hinges. Owners report visible cracks, rattles, water intrusion, and in more serious cases separation of the rear glass hinge area. Ford recalled 2002-2003 Explorers (NHTSA 04V442, Ford 04S20) because the liftgate glass strut could disengage or the glass hinge could fracture, and owner complaints frequently mention the cosmetic damage progressing into functional liftgate issues.

On the 2002-2010 Ford Explorer, rear wheel bearing and hub assemblies are a frequent wear/failure item on independent rear suspension Explorers from this period. Owners commonly report a humming or growling noise that increases with road speed and can be mistaken for tire noise or differential problems. In some cases, excessive play also affects wheel speed sensor readings and can trigger ABS or traction control warnings.

On the 2002-2010 Ford Explorer, the 2002-2010 Explorer/Mountaineer/Sport Trac door handles use brittle plastic pivot pieces in the latch/handle mechanism. The exterior handle typically cracks first and jams the linkage, then the interior handle snaps when forced. Owners are eventually left with doors that won't open from inside or outside. It is an extremely common wear complaint with no recall — treated by Ford as normal wear-and-tear.