The 1992 Mazda Navajo is a rebadged Ford Explorer sharing the same 4.0L OHV V6 and drivetrain. Expect typical Ford Ranger/Explorer issues: head gasket failures, transmission cooler leaks, and A4LD automatic transmission problems that often lead to major rebuilds.
4.0L OHV Head Gasket Failure
Common · high severityTypical onset: 80,000-150,000 mi
Symptoms: White smoke from exhaust on cold start, Coolant loss with no visible leaks, Overheating under load, Milky oil on dipstick or oil cap, Rough idle when warmed up
Fix: Requires cylinder head removal on both banks, resurfacing, new gaskets, and timing set inspection. 12-16 hours labor. Many shops recommend doing both heads even if only one failed since the other typically follows within 20k miles.
Estimated cost: $1,800-3,200
Transmission Oil Cooler Line Corrosion and Internal Cooler Failure
Common · high severityTypical onset: 70,000-120,000 mi
Symptoms: Transmission fluid leaking near radiator, Pink or milky transmission fluid (coolant mixing), Transmission slipping or delayed engagement, Sudden transmission failure after coolant contamination
Fix: Steel cooler lines rust through at frame contact points. Worse: internal radiator cooler can rupture, mixing coolant into ATF and destroying the A4LD transmission within miles. Fix requires line replacement (2-3 hours) or full transmission rebuild if contamination occurred (8-12 hours plus radiator).
Estimated cost: $300-600 lines only, $2,500-4,000 with transmission rebuild
A4LD Automatic Transmission Failure
Common · high severityTypical onset: 100,000-150,000 mi
Symptoms: Harsh 1-2 or 2-3 shifts, Slipping in 3rd or 4th gear under load, No overdrive engagement, Delayed engagement from Park to Drive, Burnt transmission fluid smell
Fix: The A4LD is notoriously weak behind the 4.0L V6. Overdrive band and clutch pack failures are common. Rebuild requires 10-14 hours with upgraded components recommended. Many opt for used transmission swaps at 6-8 hours labor.
Estimated cost: $1,800-3,200 rebuild, $1,200-2,000 used swap
Front Axle Vacuum Hub Lock Failure (4WD models)
Occasional · medium severityTypical onset: 60,000-100,000 mi
Symptoms: 4WD won't engage or engages intermittently, Grinding noise from front wheels in 4WD, 4WD light flashing on dash, One front wheel spins freely in 4WD
Fix: Vacuum-actuated hubs and lines crack or leak. Diagnosis requires vacuum testing. Most techs convert to manual locking hubs (2-3 hours) rather than replacing vacuum components which fail again. OEM vacuum repair is 3-5 hours with multiple components.
Estimated cost: $400-700 manual hub conversion, $600-1,000 vacuum system repair
Timing Cover Oil Leak and Front Seal Failure
Common · medium severityTypical onset: 90,000-140,000 mi
Symptoms: Oil pooling under front of engine, Oil spray on underside of hood, Low oil level between changes, Oil visible around harmonic balancer
Fix: Front cover gasket and crankshaft front seal leak as engine ages. Requires timing cover removal, new gasket set, and seal replacement. 6-8 hours labor. Smart to replace water pump and timing set while in there since they're accessible.
Estimated cost: $800-1,400 seal and gasket only, $1,200-1,800 with water pump and timing
Fuel Pump Failure
Occasional · high severityTypical onset: 90,000-150,000 mi
Symptoms: No start with crank but no catch, Stalling at idle or under acceleration, Hard starting when hot, Loss of power at highway speeds, Fuel pump whining from tank
Fix: In-tank electric pump fails. Requires tank drop and pump/sender assembly replacement. 2.5-4 hours labor depending on fuel level and rust. Replace fuel filter at same time (always under vehicle on frame rail).
Estimated cost: $500-900
Brake Booster Vacuum Leak
Occasional · medium severityTypical onset: 80,000-120,000 mi
Symptoms: Hard brake pedal requiring excessive force, Hissing sound at brake pedal, Rough idle that smooths when brakes applied, Engine stalls when coming to stop
Fix: Brake booster diaphragm develops vacuum leak (referenced in NHTSA recalls). Replacement requires booster removal and master cylinder R&R, then brake bleeding. 3-4 hours labor. Test by pinching vacuum line to booster with engine running.
Estimated cost: $400-700
Only buy if you find one with documented head gasket replacement and transmission service history — budget $3-5k for deferred maintenance on any neglected example, and these were almost all neglected.
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.