Some 2009-2020 Ford and Lincoln vehicles equipped with turbochargers may exhibit an oil leak from the turbocharger oil supply or return tubes, O-rings or 6.7L pedestal gasket. Although oil may collect on the turbocharger, it is very rare for a turbocharger to leak oil. To isolate the source of the leak, refer to Workshop Manual (WSM), Section 303-00 General Information > Diagnosis and Testing > Engine > Engine Oil Leaks - Fluorescent Oil Additive Method procedure. When an oil leak is present at a turbocharger oil supply or drain tube, remove the affected oil tube and inspect for damage, and replace the O-ring seals, pedestal gasket or oil tube as required. Refer to WSM, Section 303-04. For c
full bulletin at NHTSA ↗2011 Ford Flex engine problems
moderate 21 complaints filed with NHTSA · avg repair $3,100 · see engine across all vehicles →
Failure mileage
Complaints
21
Recalls
0
Avg fix
$3,100
1injury
When does it fail?
Of the 21 engine complaints filed for the 2011 Ford Flex, here's the actual mileage breakdown — failures cluster heaviest at 75,000-100,000 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
Among the 9 model years of Ford Flex in our records for engine problems, this one ranks #3 by owner-complaint volume.
No new NHTSA engine complaint has been filed on this vehicle in over 8 years — the issue may be aging out of the active population.
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 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 ↗For 2010-2019 vehicles equipped with turbocharged engines, when diagnosing and/or replacing turbo related concerns, all steps within the Workshop Manual (WSM) procedure must be followed including replacement of all mandatory discarded parts. For all turbocharged engine applications, the turbocharger oil supply filter (6C683 gas engine/6L625 connector style or 6A968 diesel engine) must be replaced whenever the turbocharger or the turbocharger oil supply tube are replaced. Turbocharger bearing failure may occur if oil starvation occurs due to a restricted filter.
full bulletin at NHTSA ↗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 ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
The 2011 Flex develops critical engine problems that often go undiagnosed by standard dealer scans. Water pump failures dominate complaints—the 3.5L engine's chain-driven ceramic pump fails between 79,000 and 146,000 miles, allowing coolant to mix with oil and destroying heads, gaskets, and ultimately the entire engine. Multiple owners report needing $8,000+ engine replacements with no manufacturer support. Timing chains also rattle and fracture, though Ford recalled the same defect in the F-150 EcoBoost but not the Flex.
EcoBoost owners report detonation at low mileage followed by persistent shuddering and acceleration hesitation that worsens in wet weather. Multiple sensor replacements and even a transmission rebuild provide only temporary relief. Turbochargers fail prematurely at 60k–70k miles, shedding metal into the oil and destroying engines. The exhaust manifold breaks internally, sending chunks into the turbo.
Wet conditions trigger dangerous stalling with no warning lights—rain, snow, car washes, even puddles cause the engine to quit. One owner reported her daughter needed ER treatment after the vehicle stalled en route to the hospital. Some failures generate no diagnostic codes whatsoever, requiring special event-recording devices to capture the fault. Dealers often cannot diagnose or fix problems even after multiple visits. Exhaust components rust excessively within months of replacement.
Same Ford Flex engine reports on nearby years: 2009 · 2010 · 2013 · 2014
Failure modes owners describe
Intermittent stalling with no diagnostic codes
Engine stalls without triggering check engine light or fault codes on standard diagnostics. Problem detected only through event-recording diagnostic device ('black box'). Root cause identified as faulty throttle body.
When: After 1-2 years of ownership; initially failed diagnostic at dealer
Symptoms owners cite: Stalling while driving; No check engine light; No fault codes on standard computer scan
Repairs/costs cited: Throttle body replacement required; owner had to pay $108.70 for initial diagnostic scan before black box device was suggested
Post-detonation drivability issues (EcoBoost 3.5L)
Following engine detonation/backfire at low mileage, vehicle exhibits persistent shuddering, stammering, and acceleration hesitation. Problem varies with weather and worsens in wet/humid conditions. Multiple sensor replacements and transmission rebuild provided only temporary relief. No diagnostic codes generated despite severe symptoms.
When: Occurred at 7,500 miles; persisted over 3+ years
Symptoms owners cite: Engine detonation/backfire; Shuddering and shaking; Stammering/hesitation on acceleration; Worse in rain and high humidity; Poor fuel economy (14.2 vs rated 18 MPG)
Repairs/costs cited: Transmission rebuilt; three different sensors replaced on EcoBoost engine (33 sensors available); temporary improvements only
Recalls/TSBs owners mention: Ford Customer Service contacted 4-5 times but refused ownership; service department reported inability to contact Ford Technical Group without failure codes
Exhaust manifold deterioration causing turbo damage
Exhaust manifold composed of stainless steel exterior and cast iron interior breaks apart internally, sending metal chunks into turbocharger and intake system. Turbochargers destroyed twice before manifold root cause identified. Metal debris blocks exhaust passages, causing compression loss in cylinders 1 and 3.
When: Manifold failure occurred during turbo operation; issue discovered after multiple turbo replacements
Symptoms owners cite: Loss of turbo boost; Turbocharger failure/explosion of internal parts; Metal shavings in intake system; Ruptured turbo boot; Compression loss in cylinders 1 and 3
Repairs/costs cited: Turbochargers replaced twice; exhaust manifold eventually replaced; owner reports Ford refused responsibility for damages and reimbursement; smog failure after repair
Water pump failure and engine damage (ceramic)
Water pump fails internally, allowing coolant to mix with engine oil and causing head gasket failure. O-rings fail, propeller breaks apart and blocks water passages. Multiple owners report same failure pattern on 3.5L engine with chain-driven water pump. Failures occur between 79,000 and 146,000 miles, requiring engine replacement.
When: 79,000–146,000 miles
Symptoms owners cite: Engine overheating; Coolant mixing with oil; Blown head gasket; Water detected in engine; Loss of coolant/fluids; Engine seizure
Repairs/costs cited: New engine required ($8,000 reported); water pump replacement attempted; ceramic water pump noted as defective design
Recalls/TSBs owners mention: No recalls confirmed by manufacturer; owner reports water pump recall exists for similar Ford engines but not applied to Flex
Timing chain failure and engine lockup
Timing chain rattles at startup and deteriorates. Chain can fracture and cause piston/valve damage, leading to engine stall and complete engine failure. Similar issue was recalled on F-150 EcoBoost but not addressed for Flex.
When: 79,000 miles (one case); issue worsens over time
Symptoms owners cite: Timing chain rattle on cold startup; Timing chain fracture; Bent engine valves; Engine stall; Engine lockup
Repairs/costs cited: Engine requires replacement after chain failure and valve damage
Recalls/TSBs owners mention: Similar issue covered under recall for F-150 EcoBoost; no recall issued for Flex
Turbocharger failure (EcoBoost)
Turbochargers fail prematurely and repeatedly. Metal shavings appear in oil filter, clogging oil lines and potentially destroying engine. Sudden loss of power during highway driving.
When: 62,000–68,260 miles
Symptoms owners cite: Sudden loss of engine power; Turbocharger failure; Metal shavings in oil filter; Clogged oil lines; Shuddering at highway speed
Repairs/costs cited: Turbochargers replaced; metal contamination suggests internal engine damage; likely engine destruction
Wet-weather stalling
Engine stalls in rain, snow, car washes, and even puddles. Vehicle loses power unexpectedly in wet conditions, creating dangerous driving situations. Multiple dealer visits and extended service attempts have not resolved the problem.
When: Early in ownership; ongoing issue
Symptoms owners cite: Stalling in rain and snow; Stalling in car washes; Stalling in puddles; Hesitation on highways ('putt putt'); Near-stall conditions
Repairs/costs cited: Vehicle serviced at least 4 times; one visit lasted 4 weeks without resolution
Exhaust system rust and structural failure
Exhaust muffler holding bracket rusts severely within 7,500 miles of warranty repair replacement. Excessive rust creates hazard of muffler detachment during driving.
When: 7,500 miles after replacement (within first year)
Symptoms owners cite: Severe rust on muffler support bracket; Risk of muffler detachment
Repairs/costs cited: Muffler bracket replaced by dealer (05/03/11); replacement part also severely rusted
Cabin air odor (sulfur/catalytic converter smell)
Strong sulfur smell enters cabin after hard acceleration, similar to catalytic converter odor. Service department can replicate but cannot diagnose or fix the problem.
When: During hard acceleration events
Symptoms owners cite: Strong sulfur odor in cabin; Smell occurs after hard acceleration
Heating/cooling system odor
Terrible smell from air conditioning unit. Dealer repeatedly replaces filter but never resolves underlying issue. Smell may indicate toxic contamination.
When: Ongoing from purchase
Symptoms owners cite: Foul odor from AC unit; Window squealing (related complaint); Smell persists despite filter replacement
Repairs/costs cited: Filter replaced multiple times; dealer refuses to test air quality
Synthesized from 21 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 1 most recent
Car has meticulous service record, I had 86k miles on car. The car would not start towed to dealership. The ceramic water pump exploded, causing coolent to mix with oil. Now I need new engine $8,000. I have used same dealership for car maintenance for last 7 years.
Had engine trouble with your 2011 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 2011 Ford Flex?
It's a documented issue but not catastrophic. 21 complaints have been filed. Repairs average $3,100 and most owners catch it before it causes a breakdown.
At what mileage does the engine typically fail?
Across the 19 complaints that reported odometer mileage, most engine failures cluster between 30,000 and 113,000 miles, with the median around 79,000. A quarter of owners report trouble before 30,000; a quarter make it past 113,000. 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/2011/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.