The first-generation Explorer is a capable platform with a bulletproof 4.0L OHV V6, but it's plagued by transmission cooler failures that kill A4LD/4R55E automatics, along with typical high-mileage engine wear issues and some Ford-specific body quirks.
Transmission Oil Cooler Failure Leading to Transmission Destruction
Common · high severityTypical onset: 80,000-150,000 mi
Symptoms: Transmission slipping or refusing to shift, Pink or milky transmission fluid (coolant contamination), Sudden transmission failure after coolant system work, Overheating transmission even with normal operation
Fix: The internal transmission cooler in the radiator fails, allowing coolant and ATF to mix, which destroys clutch packs and seals. Fix requires radiator replacement, external cooler install, full transmission flush or rebuild. If caught early (just cooler leak), 3-4 hours labor. If transmission is damaged, add 8-12 hours for rebuild or R&R.
Estimated cost: $800-3,500
4.0L OHV Head Gasket Failure and Cylinder Head Cracking
Occasional · high severityTypical onset: 120,000-180,000 mi
Symptoms: White smoke from exhaust on startup, Coolant loss with no visible leaks, Overheating under load, Rough idle or misfire on cold start, Oil in coolant or vice versa
Fix: The OHV 4.0L develops head gasket leaks and occasionally cracks heads between cylinders, especially if overheated. Both heads typically done at once with machine work. Expect 10-14 hours labor plus machining costs. Often triggers other discoveries (warped heads, corroded coolant passages).
Estimated cost: $1,800-3,200
Lower Engine Wear: Piston Ring and Bearing Failures
Occasional · high severityTypical onset: 150,000-220,000 mi
Symptoms: Heavy blue smoke on deceleration or startup, Excessive oil consumption (1 qt per 500-1,000 mi), Knocking or rattling from bottom end, Low oil pressure at idle when hot, Metal shavings in oil filter
Fix: The 4.0L OHV can wear rings and bearings with neglected oil changes or prolonged overheating. Ring job alone is 12-16 hours; full rebuild with crank, bearings, and machine work runs 18-24 hours. Many opt for a used engine swap (6-10 hours) instead given vehicle age.
Estimated cost: $2,200-4,800
Liftgate Strut and Glass Hinge Failures
Common · low severitySymptoms: Liftgate won't stay open or falls unexpectedly, Glass window won't stay up, Hinge hardware cracked or broken, Struts leaking or compressed
Fix: Both liftgate struts and rear glass struts fail regularly. Glass hinge hardware also cracks. Struts are simple replacements (0.5-1 hour total). Glass hinge repair kits available but require patience. NHTSA recalled some for strut failures.
Estimated cost: $150-400
A4LD and Early 4R55E Transmission Internal Failures
Common · high severityTypical onset: 100,000-160,000 mi
Symptoms: Harsh or delayed 2-3 shift, Slipping in overdrive, No 3rd or 4th gear, Transmission shudder on light throttle, Metal shavings in pan
Fix: Even without cooler contamination, these transmissions have weak OD bands, worn clutches, and valve body issues. The A4LD (through '94) is especially fragile. Rebuild is 8-12 hours; used replacement 6-8 hours. Add external cooler regardless.
Estimated cost: $1,800-3,000
Fuel System Issues: Clogged Filters and Pump Failures
Occasional · medium severityTypical onset: 90,000-140,000 mi
Symptoms: Hard starting when hot, Hesitation or stumble under load, Stalling at idle after driving, Loss of power on highway, Whining noise from fuel tank
Fix: Neglected fuel filter changes kill the in-tank pump. Filter is easy (0.5 hour), but pump requires tank drop (2-3 hours). Many Explorers run original pumps past 150k if filters were changed every 30k. Don't skip this maintenance.
Estimated cost: $400-800
Vacuum-Operated 4WD System Leaks and Failures
Occasional · medium severitySymptoms: 4WD won't engage or disengage, Hissing from dashboard or under hood, 4WD engages randomly, Rough idle (vacuum leak)
Fix: The vacuum lines and solenoids for 4WD engagement dry-rot and leak. Diagnosis can be tedious (1-2 hours); repairs range from simple hose replacement to transfer case motor or solenoid swap. Some convert to manual hubs to bypass the system entirely.
Estimated cost: $200-700
Buy one only if transmission has been rebuilt with external cooler added and seller has oil-change records; otherwise you're gambling on a $3,000 surprise within 20,000 miles.
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.