THINK TWICE

Exhaust odor and carbon monoxide entering the cabin is the defining safety topic of the 2011-2019 Explorer: NHTSA opened investigation PE16008 (2016) and escalated it to Engineering Analysis EA17002 (2017), reviewing thousands of owner complaints and VOQs of an exhaust smell -- often under acceleration or with the HVAC running -- with alleged nausea, headaches and lightheadedness consistent with CO exposure. It is worst on the Police Interceptor Utility. In closing EA17002 (2023) NHTSA did NOT find a base-vehicle defect: the highest measured cabin CO traced to police up-fitting and to rear crash-damage sealing, and Ford field service actions (an HVAC reprogramming plus sealing repairs) reduced CO below accepted health limits. The odor complaints are real regardless; hundreds appear in the federal record.

Check — Confirm Ford's customer-satisfaction / field-service work for exhaust odor was performed (the consumer 17N03 and police 17B25 actions, including HVAC reprogramming). On the test drive, accelerate hard with the HVAC on and windows up and smell for exhaust in the cabin. Be extra wary of ex-police units and any Explorer with prior rear-end collision repair, where sealing was most often compromised.

The 3.5L Ti-VCT V6 (Cyclone) drives its water pump internally, off the timing chain behind the timing cover, so when the pump's seal fails coolant leaks INTERNALLY into the engine rather than dripping on the ground -- often with little external warning until the engine overheats or is damaged. Replacing it is an engine-out / timing-cover job, with owners quoting roughly 1,500 to 4,000 dollars; several federal complaint texts call it a known issue with no recall and cite a class-action. It shows up across a wide mileage band, not just at high mileage.

Check — On a 3.5L V6 Explorer, check for coolant loss with no visible external leak, milky oil or coolant/oil mixing on the dipstick, and any overheating history; ask whether the water pump has already been replaced. Treat an unaddressed internal water pump as a major budget line on a higher-mileage 3.5.

On all-wheel-drive Explorers the Power Transfer Unit (PTU) -- the small gearbox that sends drive to the rear axle -- runs hot and can fail: owners report the internal bearings wearing out, whining or grinding, fluid burning, and the whole unit needing replacement, sometimes before 60-70k miles. The PTU fluid is not on the routine maintenance schedule and the unit has no easy service point, so it often cooks quietly until it is damaged. Federal complaint texts describe PTU bearing failure and burnt fluid on these AWD Explorers; a failed PTU is an expensive driveline repair, not a simple fluid change.

Check — On an AWD example, listen for a whine or grinding from under the vehicle that rises with speed, and ask whether the PTU fluid has ever been changed (a good indie shop services it ~every 30-60k miles even though Ford does not call for it). Budget for a PTU replacement on a high-mileage AWD Explorer with no fluid history.

The 6-speed automatic (6F-family) draws a steady stream of complaints for harsh or erratic shifting, shudder, hesitation and jerking, and in the worst cases a loss of forward or reverse drive. The texts describe clunks on the 1-2 change, delayed engagement, and shudder under light throttle. Many are driveability rather than catastrophic failure, but they are common enough to test for deliberately on this generation.

Check — On the test drive work the transmission through slow and hard acceleration, stop-and-go, and downshifts under braking; feel for shudder, harsh or delayed shifts, or clunking, and confirm clean engagement into both drive and reverse. Ask when the transmission fluid was last serviced and whether any shift-quality reflash or repair was done.