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 2008 Mercury Mariner owners, lightly cleaned up (personal details are redacted by NHTSA).
My wife was driving on her way home, and out of nowhere the steering felt weird, and while driving the car shut off. No power steering or power brakes (due to engine shutting off) and we do not know why this happened.
The car is reving high and accelerating poorly. Then the red triangle light telling me to stop safety now comes on causing me to pull over and shut car off. I turn the car back on and it drives but with same issues. Look on the carcomplaint.com website for TSB-09-19-12 and TSB-08-24-5 which detail what my car is doing and makes it appear like there is a cooling pump recall. Ford just told me there are no recalls listed for my VIN though. The frequency of which the red triangle light comes on is increasing this month. It was every few months and now it is weekly-daily.
Tl* the contact owns a 2008 Mercury Mariner. While driving 40 MPH, the vehicle hesitated and would not accelerate past 25 MPH. In addition, the vehicle accelerated rapidly without warning. The contact stated that the vehicle shut off on numerous occasions and the check engine indicator illuminated briefly without warning. The vehicle was not repaired the manufacturer was made aware of the failures. The failure mileage was 44,000. Updated 08/04/17
My vehicle is having trouble steering, took my vehicle to the repair shop and they informed that it was a recall on it. I took my vehicle to the dealership and they told me since my VIN number for me vehicle was not in the recall there was nothing that they could do and wanted to charge me $125.00 to put it on their machine, I already to my SUV to the shop and they informed to go to the dealership
Tl* the contact owns a 2008 Mercury Mariner. The contact stated that while driving at 15 MPH, the vehicle stalled without warning. The contact stated that the vehicle displayed "power steering fault" warning message. The vehicle was not diagnosed or repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 100,000.
Tl* the contact owns a 2008 Mercury Mariner. While driving 45 MPH, the vehicle stalled without warning. The contact was unable to restart the vehicle. The vehicle was towed to the contact's residence. The vehicle was not diagnosed or repaired. The manufacturer was not notified of the failure. The approximate failure mileage was 125,000.
The throttle is held open when the cruise control is employed but remains open when the cruise control is turned off both by using the off button and brake application. This happens at 75-80 MPH on interstate highways in az and ut. The power brake booster is ineffective with no intake vacuum. This is very dangerous.
I had just made a right turn and was proceeding down the block when I heard a sudden "click" and lost power. I couldn't steer and there was no power. I managed to get the car over to the curb and turn off the engine. I restarted it a few minutes later and it started up OK. However, the rsc warning light stayed on even though I had never pressed that button. This is not the first time this has happened. The first time it happened I was told it was a battery problem so I got a new battery. That was less than a year ago and I can't imagine I need a new battery that often - that simply needing a new battery will cause my car to fail! …
Driving the truck through a drive thru at a mcdonalds with my 2 year old son in backseat and the power steering stopped working as proceeding thru drive thru, almost hitting the building having no control over truck. Very dangerous problem with this make and model/this is a safety hazard and someone will end up as a casualty if this problem with steering not recalled by Ford. I am a 280 guy and could barely steer the truck until I shut it of and restarted it. Also oil leak on engine for most of these v6 mariners and escapes is above oil pan by harmonic balancer,Ford refuses to admit they did a horrible job putting together the bottom end of these engines.overall Ford needs to reconsider what should be a recall on their vehicles before someone gets seriously injured or killed. I am a ase certified mechanic and have never encountered such problems with a vehicle.
I was attempting to exit a parking lot and vehicle stalled and would not accelerate. I coasted back into a parking space, shut off engine and made a few more attempts with the same result each time. I shut vehicle off and waited for roughly twenty minutes and tried again. Vehicle did engage and I was able to exit parking structure however, vehicle stalled in the middle of the road. Fortunately, there was light traffic and I was able to coast back into parking lot. Problem was subsequently diagnosed as bad binding throttle cable. The cable was replaced at my expense. February 24 and 25 of 2014, vehicle stalled while in traffic, lost power and again pedal stuck and vehicle would not engage. Subsequent diagnosis is replacement of throttle body at my expense. This is extremely expensive and potentially dangerous.
Engine complaints in other Mariner years
Frequently asked questions
How common are engine problems on the 2008 Mercury Mariner?
NHTSA has 20 complaints about the engine & cooling of the 2008 Mercury Mariner, 4% of the model year's 461 complaints. The component named most often is engine (2 mentions).
Is there a recall for 2008 Mercury Mariner engine problems?
No. NHTSA lists no engine & cooling recall for the 2008 Mercury Mariner, though it has 3 recalls 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 2008 Mercury Mariner engine problems start?
Half of the complaints with a recorded mileage happened before about 100,000 miles, and 20% before 25,000 miles.
Is it dangerous?
Owners linked 1 crash, 0 fires 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.