One of my best buddies owns a 94 explorer. He has to get rid of it soon because over the summer, while driving back from the states, something blew in the engine and he was told that the entire engine needs to be replaced, which is obviously very costly. He now can't drive the car over 45 kph on the advice of his mechanic until he fixes it. Other problems he has had over the years was the passenger door won't lock, Always seems to have a headlight out, and to replace the brake pads several times and blown speaker (that one's his fault. I keep telling him to turn down the music!)
He still likes the vehicle though. It is tremendous in snow. Won't get stuck anywhere. Like S60 said, if you can deal with the minor problems it has now, then it should be an alright vehicle, but just be aware that these problems will not go away once they start. But it has lasted him a good 8 years though and just started to fall apart recently. Prior to that, he had very little problems.
Good luck and let us know what you decide!
