Two problems related to loud engine noise have been reported for the 2004 Mercury Mountaineer. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Mercury Mountaineer based on all problems reported for the 2004 Mountaineer.
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.
While driving there was a very loud noise from the front of the vehicle. Consumer pulled off the road, and called road side assistant. Vehicle was towed to the dealer, who performed an oil change because of mileage at the time of the incident. Noise recurred the following day. Vehicle was taken back to the dealership, who indicated that the driveshaft was defective, and needed to be replaced. Vehicle is currently at the dealership being inspected.