Which parts fail
Components named in complaints (engine, cooling system, oil leaks, timing chain, exhaust).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2010 Ford Flex owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owns a 2010 Ford Flex. The contact stated while driving 50 MPH, the steering wheel became firm, and the vehicle lost motive power. The contact pulled over to the side of the road and was able to restart the vehicle after 3 attempts. No warning light was illuminated. The vehicle was taken to an independent mechanic to be diagnosed. The contact was informed that the failure was due to the oil mixing with the coolant. The manufacturer was made aware of the failure and determined that the vehicle was not under warranty. The failure mileage was approximately 148,000.
My 2010 Ford Flex began inadvertently surging forward in acceleration without me making it do this exactly 3 months after I purchased the vehicle. The Ford Dealer was unable to re-produce the problem on several occasions and said my vehicle was fine. No error messages reported in the computer. This has continued to happen sporadically since ownership. I have had another Ford Dealership (as well as an independent mechanic) try and reproduce and diagnose the problem with no luck. Several weeks ago I was driving my vehicle in my residential neighborhood when all of a sudden my car surged forward with great acceleration with no warning. I had to swerve into a driveway and cut the vehicle off to get the vehicle under control. I am 82 and have a heart condition. This safety issue is critical as someone could get hurt or killed. …
While driving at 65mph, vehicle started to accelerate funny and cel came on. was getting on the freeway and the vehicle overheated and CEL light came on. I was able to safely pull over before the vehicle died. Got vehicle towed to my home and when engine oil was checked, it was discovered that there was coolant in the oil. Took to a local shop where it was determined that the water pump had failed and dumped all of the coolant into the oil pan. Estimated cost of repair with labor is $5,000. Failure mileage was ~192,000. The oil was in good standing and gold in color 12 hours prior and was only driven ~45 miles at highway speeds before the failure happened. From what I can tell, this was a catastrophic failure of the water pump bearing seal that happened almost instantaneously. This needs to be looked into, as the repair bill does not match the issue. …
Tl* the contact owns a 2010 Ford Flex. While driving at an unknown speed, the turbos failed and caused oil to burn through the motor. The failure created an excessive amount of smoke to come through the exhaust pipes. Hubler Ford in shelbyville, indiana was made aware of the recall and stated that the parts were unavailable. The manufacturer was made aware of the failure. The failure mileage was approximately 110,000.
While merging onto a highway the engine suddenly lost power and began shuttering/vibrating badly. This loss of power nearly caused a severe accident as the sudden slow down caused cars behind us to take evasive action. The check engine light illuminated immediately. We drove the car to the dealership per instructions from the service rep. The vehicle has the 3.5l EcoBoost engine. The service tech first said an ignition coil went bad and replaced it, only to discover that it did not fix the problem. They did a cylinder compression test and were loosing compression in one cylinder. The engine had to be disassembled to diagnose the problem. The service tech found the cylinder rings had failed in one cylinder and now has to replace the whole engine at a cost of $7,800. The engine only has 55,000 miles on it! …
Tl* the contact owns a 2010 Ford Flex. While driving 30 MPH, the contact heard a popping noise coming from the vehicle and the air conditioning began to blow out hot air. The contact also noticed that the vehicle began to lose power, overheat, and the check engine warning indicator illuminated. The contact drove to ken garff west valley Ford (4091 w 3500 s, west valley city, ut 84120, 801- 559-0314) where it was diagnosed that the water pump failed and caused the vehicle to overheat. The contact stated that the entire engine was ruined due to the failure and was informed that an engine replacement would cost approximately $8,000. The manufacturer was not notified of the failure. The vehicle had not been repaired. The failure mileage was 178,000. The VIN was unknown.
Tl* the contact owns a 2010 Ford Flex. The contact stated while stopped at a stop sign the vehicle became inoperable. The vehicle was towed to the residence. The contact stated the water pump failed which flooded the engine. The vehicle was taken to planet Ford located at (20403 I-45, spring, tx 77388 [phone]) and the contact was informed that a diagnostic test could not be scheduled for 6-8 weeks. The manufacturer was made aware of the failure. The manufacturer stated that the engine needed to be replaced. The vehicle was not repaired. The approximate failure mileage was 192,000.
2010 Ford Flex with Duratec 3.5l engine - sudden water pump failure causes coolant to flood the engine, which can cause the engine to overheat and cut off while driving, without warning. This happened to me while driving to work. Luckily I was able to pull off the road safely. There are many others with this engine who have had this problem, because the water pump is inside the engine-- see e.g. Http://www.carproblemzoo.com/Ford/Flex/water-pump-problems.php and https://www.ktmc.com/Ford-Lincoln-water-pump-engine-failure .
Engine stalls out, while driving the car around town. Has occurred twice, separated by a few weeks. No warning, or engine trouble or indicator lights prior or after the event. Occurs while driving a low to moderate speed both times, about 30 MPH. Car can be restarted immediately after and drives fine. Have had mechanics check fuel and air sensors and lines and find no obvious defects. Other Ford Flex owners report similar problem since 2009. Rumor is that replacing the throttle body corrects the issue.
Tl* the contact owns a 2010 Ford Flex. The contact stated that while driving approximately 70 MPH, the vehicle stalled without warning. The vehicle was towed to the dealer where it was diagnosed that there was a misfire on cylinder number 3 and 2 and that the fuel injector needed to be replaced. The vehicle was repaired, however, the failure recurred while driving approximately 50 MPH. The vehicle restarted. The manufacturer was made aware of the failure. The approximate failure mileage was 47,000.
Engine complaints in other Flex years
Frequently asked questions
How common are engine problems on the 2010 Ford Flex?
NHTSA has 38 complaints about the engine & cooling of the 2010 Ford Flex, 27% of the model year's 139 complaints. The component named most often is engine (2 mentions).
Is there a recall for 2010 Ford Flex engine problems?
No. NHTSA lists no engine & cooling recall for the 2010 Ford Flex, though it has 1 recall for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2010 Ford Flex engine problems start?
Half of the complaints with a recorded mileage happened before about 74,000 miles, and 24% before 25,000 miles.
Is it dangerous?
Owners linked 0 crashes, 1 fire and 0 injuries to engine & cooling problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.