Some 2009-2017 Expedition/Navigator, 2009-2014 F-150/Mustang, 2008-2009 Sable, 2008-2019 Taurus/Flex/MKT, 2013-2019 Police Interceptor Sedan/Utility, and 2011-2019 Explorer vehicles may exhibit inoperative or intermittent HVAC blower motor function at various fan speed settings. This may be due to a poor electrical connection at the blower motor speed control. If the blower motor speed control is determined to be the causal part, replacement of the electrical connector pigtail harness (14S411) to the blower motor speed control is also recommended to avoid repeat repairs. Refer to Wiring Diagram, Cell 5 for recommended splicing procedures. Refer to Wiring Diagram, Cells 54/55 to obtain the se
full bulletin at NHTSA ↗2009 Ford Flex engine problems
severe 33 complaints filed with NHTSA · avg repair $3,100 · see engine across all vehicles →
Failure mileage
Complaints
33
Recalls
0
Avg fix
$3,100
1fire
2injuries
When does it fail?
Of the 33 engine complaints filed for the 2009 Ford Flex, here's the actual mileage breakdown — failures cluster heaviest at 100,000-125,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
What stands out
Of the 9 model years of Ford Flex we track for engine problems, this one carries the most owner complaints on file — 33.
Owners have filed 33 engine complaints with NHTSA against this vehicle, but no formal recall covers the issue — the federal record reflects what manufacturers have admitted, not everything owners are reporting.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering engine on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
Some 2007-2016 Edge/MKX/Flex/MKT/MKZ/MKS/Taurus/Police Interceptor Sedan/Explorer/Police Interceptor Utility vehicles equipped with AWD and built on or before 30-Jun-2016 may exhibit a propane or natural gas odor during idle or low speed driving. This may be due to break down of the power transfer unit (PTU) fluid caused by excessive heat. If the source of the odor is identified as originating from the PTU, an idler bearing repair kit is available to repair the PTU. Refer to the Workshop Manual (WSM), Section 308-07. If the PTU is determined to be repairable, utilize kit GB5Z-7P258-A and the included instruction sheet. For claiming use causal part 7P258 and applicable labor operations in sec
full bulletin at NHTSA ↗The Powertrain Control/Emissions Diagnosis (PC/ED) manual has been revised for diagnosing electronic throttle bodies (ETBs). The ETC_ACT and ETC_DSD PIDs should not used to diagnose possible ETB concerns. The IDS has a limited refresh rate when reading these PIDs and cannot display quickly enough to validate a concern. The PCM automatically monitors these inputs more accurately and will set diagnostic trouble codes (DTCs) when appropriate. Using these PIDs for diagnostics will lead to inaccurate results and improper ETB replacements. If a concern is intermittent and no DTCs are present, refer to historical DTCs and the PC/ED, Section 3 No DTCs Present Index chart for further information.
full bulletin at NHTSA ↗FORD: WITH AUXILIARY CLIMATE CONTROL SYSTEM ON, CAN SMELL AN EXHAUST ODOR IN VEHICLE. LIKE SULFUR, AFTER HARD DRIVING CONDITIONS OR ACCELERATION. MODEL 2009-14 FLEX.. UPDATE. 06/11/15.
full bulletin at NHTSA ↗FORD: IF THERE IS AN INTERMITTENT LACK OF POWER, SURGE, OR HESITATION WHILE DRIVING THE BRAKES WILL OVERRIDE ACCELERATION.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Owners report a cluster of serious failures across cooling, ignition, and fuel management in 2009 Ford Flex engines. The most common complaint is radiator cooling fan failure—owners describe fans stopping suddenly at idle or low speed, causing the engine to overheat even in moderate weather. Early warning is typically warm AC air at idle; some owners report no temperature warning light until after reduced-power mode engages. Owners also report engines dying without warning during normal driving—at low speeds, on highway ramps, even while turning. These stalls often occur without illuminating check-engine lights initially, and power steering and brakes are lost during the event. A few owners describe violent shaking or uncontrolled engine revving before stalls.
Less frequently, owners report throttle body issues, water pump failure mixing coolant into oil (requiring engine replacement), and oxygen sensor failures. One owner describes exhaust fumes backing into the cabin during acceleration. Another documents frame corrosion cracking near the engine cradle.
Ford has addressed the cooling fan issue for 2011–2012 model years under Customer Satisfaction Program 12B36, but 2009 and 2010 models are excluded. Owners express frustration that similar hardware defects are not recalled across all affected years. Repairs cited range from $700 (throttle body) to $1,094 (cooling fan module) to $8,000 (engine replacement) when out of warranty.
Same Ford Flex engine reports on nearby years: 2010 · 2011
Failure modes owners describe
Radiator cooling fan failure
Both radiator cooling fans become inoperative or fail intermittently, causing engine overheating. Engine enters reduced-power mode or overheats at idle or low speed. Owners report warm AC blowing at idle as early sign.
When: Typically at idle or during low-speed driving; one owner reports failure at 55,000 miles; another at 47,813 miles; some within first few years of ownership
Symptoms owners cite: Engine overheating at idle or slow speed; AC blowing warm air when stopped; Temperature warning light illuminates late or not at all; Reduced power mode engagement; Fans tested inoperative
Repairs/costs cited: Fan assembly replacement; cooling fan relay replacement; cooling fan module replacement ($1,094); some owners purchase aftermarket fans
Recalls/TSBs owners mention: Ford Customer Satisfaction Program 12B36 covers 2011–2012 model years only; 2009–2010 excluded. Some repairs covered under extended care plan with $100 deductible.
Engine stalling without warning
Engine shuts off unexpectedly during normal driving—at low speeds, on highways, during turns, or at idle—without warning lights or clear cause. Power steering and brakes lost. Restarts easily once vehicle is in neutral or park.
When: At various speeds: 5 mph, 20–30 mph, 40 mph, 50 mph, 55 mph, 65 mph; at idle; at stop lights; some owners report multiple occurrences
Symptoms owners cite: Engine dies abruptly; No warning lights initially; Power steering fails during stall; Braking becomes difficult; Vehicle restarts easily after neutral/park
Repairs/costs cited: PCM (engine control module) replacement; wiring harness replacement; software update; unknown part replacement cited in at least one case; one owner reports $700 throttle body replacement
Recalls/TSBs owners mention: Dealer diagnosis; no recalls mentioned; some repairs under warranty, others owner pays
Engine overheating with cooling system control issues
Engine overheats frequently, especially at idle or during AC operation, despite no visible coolant leaks. Cooling fan module, relays, and thermostat replaced without permanent resolution. One case of ongoing overheating after multiple repair attempts.
When: During idle at stop lights; during AC operation in summer heat; one owner reports 3-year history of intermittent overheating
Symptoms owners cite: Temperature gauge rising quickly; Overheating at stop signs and idle; AC failure during overheating event; Multiple repeated failures despite repairs
Repairs/costs cited: Cooling fan module replacement ($1,094); relay replacement; thermostat replacement; vacuum testing performed; multiple repair attempts on same vehicle without permanent fix
Recalls/TSBs owners mention: None cited in these narratives
Water pump failure
Water pump suddenly fails during normal driving, allowing coolant to mix with engine oil. Results in catastrophic engine damage and need for engine replacement.
When: At 45 mph on routine driving; one owner reports failure with no prior warning signs
Symptoms owners cite: Engine stops suddenly; Coolant enters oil (visible on inspection); No prior overheating or warning signs
Repairs/costs cited: Engine replacement required; invoice cited $369,486 (total repair cost unclear); one owner reports out-of-pocket cost for used engine installation
Recalls/TSBs owners mention: None cited
Uncontrolled engine revving
Engine revs uncontrollably during low-speed driving in gear. Brakes do not slow vehicle; vehicle lurches forward or backward even with foot on brake pedal. Multiple occurrences reported.
When: During reverse in garage; during drive in parking lot; on interstate highway
Symptoms owners cite: Engine revving uncontrollably; Vehicle lurches forward or backward despite braking; Difficult to control speed and direction
Repairs/costs cited: No repair outcome cited; owner notes potential for collision; mechanic advised not to drive until diagnosed
Recalls/TSBs owners mention: None cited
Oxygen sensor failure
Oxygen sensor becomes defective, triggering check-engine light. Repair required for safeties to operate. Owner disputes need for replacement given lack of moving parts.
When: At unknown mileage; owner notes design life should exceed 150,000 miles
Symptoms owners cite: Check engine light illuminates; Safeties disabled until repair
Codes mentioned: P0422
Repairs/costs cited: Oxygen sensor replacement, cost over $400; warranty declined
Recalls/TSBs owners mention: None cited
Exhaust fumes in cabin during acceleration
Carbon monoxide and catalytic converter smell enters cabin during hard acceleration (passing gear, on-ramp entry). Occurs intermittently on roughly 1 in 4 Flex vehicles per owner estimate. Causes headache and eye burning.
When: During passing maneuvers, acceleration from on-ramps, heavy acceleration events
Symptoms owners cite: Exhaust smell in cabin; Carbon monoxide odor; Slight headache and eye burning if windows not lowered
Repairs/costs cited: Baffle replacement at exhaust system end (attempted repair); repair made no difference
Recalls/TSBs owners mention: None cited; owner notes no engineered solution exists
Total electrical power loss while driving
Complete electrical failure while in traffic—engine dies, all lights go out, accessory power lost. Occurs at low speed in heavy traffic. Vehicle restarts after power is regained.
When: Early morning in heavy freeway traffic; one instance after 650 miles of normal driving post-event
Symptoms owners cite: Complete engine shutdown; All electrical components fail; Loss of power steering and brakes; Vehicle does not restart in neutral or drive, only in park
Repairs/costs cited: New battery installed in August 2014; connections verified tight; no repair performed; issue resolved after event
Recalls/TSBs owners mention: None cited
Fuel gauge failure
Gas gauge stops functioning, showing incorrect fuel level. In one case, engine stalls despite gauge reading 1/4 tank in reserve.
When: At varying mileage; stall event reported at low speed
Symptoms owners cite: Gas light no longer illuminates or functions; Gauge reads inaccurate level; Engine stalls with fuel remaining
Repairs/costs cited: No repair cited
Recalls/TSBs owners mention: None cited
PCM and ignition control malfunction
Engine control module or related ignition system fails, causing stalling, violent shaking, and coil damage. Three melted coils and converter damage reported. Occurs suddenly without warning lights until after failure.
When: While accelerating at 70 mph on highway; instances at low speed
Symptoms owners cite: Vehicle shakes violently then stalls; Sudden loss of power on highway; Check engine light appears only after failure
Repairs/costs cited: PCM replacement; three melted ignition coils; catalytic converter replacement
Recalls/TSBs owners mention: None cited; owner calls for recall instead of TSBs
Engine frame and cradle corrosion
Engine cradle rusted through with visible cracks extending to lower control arm. Identified as factory defect presenting potential engine dropping hazard.
When: Documented in 2020; unknown mileage
Symptoms owners cite: Rust penetration through cradle; Visible cracks in cradle
Repairs/costs cited: No repair cited; mechanic identified as factory default
Recalls/TSBs owners mention: None cited
Synthesized from 33 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 3 most recent
Engine stalls despite fuel gauge reading 1/4 tank in reserve. Fill up confirms that there is in fact 1/4 tank left. Has happened several times now.
The vehicle over heats, and just gets too hot. If the a/c is running it over heats just sitting at the light. Now that it is cooler, the heater is on and it over heats just sitting at the light. I stop the car and let it cool down but it should not be operating like this. There are many problems describing this same problem and it is a factory defect and needs to be corrected. No reason just…
Tl* the contact owns a 2009 Ford flex. The contact stated while his wife was driving 55 MPH, the vehicle shifted independently into neutral. The contact stated no warning light was illuminated. The driver pulled over on the side of the road. The vehicle was restarted and driven to her destination. The vehicle was taken to the local dealer safford Ford Lincoln of salisbury located at 1902 n…
Had engine trouble with your 2009 Ford Flex?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the engine problem on the 2009 Ford Flex?
It's a meaningful issue. 33 complaints have been filed and the failure mode causes operational problems for owners. Repairs average $3,100.
At what mileage does the engine typically fail?
Across the 27 complaints that reported odometer mileage, most engine failures cluster between 25,500 and 119,000 miles, with the median around 65,000. A quarter of owners report trouble before 25,500; a quarter make it past 119,000. Maintenance history matters more than the odometer alone — this is the reported failure window, not a guarantee.
What does it cost to fix?
Independent shops typically charge around $3,100 for engine repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to engine?
No active recalls currently cover engine issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2009/Ford/Flex.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.