2004 Mercury Mountaineer - harmonic balancer failed. It was noticed when a squeaky noise was coming from the engine. Although is was caught before any serious injury occurred, this failure may have led to one. If the balancer had completely failed, it could have resulted in loss of steering and at highway speeds would have been catastrophic. Steering is lost because drive belt would have come lose. Unit was replaced at a cost of $475. Old part was saved for inspection.

- Andover, MA, USA

I started my 2004 Mercury Mountaineer the other day, and the engine started making a horrible noise, like a lawn mower, right when it started. I shut it off immediately and eventually had to get a tow truck to bring me to the Ford dealer. Luckily I wasn't driving this time when it happened. It turns out that the engine spat out a spark plug. This seems to be a chronic problem with Ford Motor Company SUV's and pick-ups. The temporary solution is to plug the socket because the threads wore out. However the spark plug was factory-installed and the issue is definitely a Ford problem. The next time, it could be either lead to a terrible accident or thousands of dollars to repair, or both.

- Cortlandt Manor, NY, USA

The vehicle stalls intermittently. The consumer has taken the vehicle to the dealer and was told that the problem did not duplicate itself.

- Dixon, IL, USA

While driving, the engine check light illuminated on the dashboard. Consumer took the vehicle to the dealership (4) times, but the problem still existed.

- Pittsburgh, PA, USA