Timing Chain went out on my Explorer with 174000 miles. Is this a factory defect?
No it is not.
4.0 overhead cam motor?
If so, this is probably a deathblow for the vehicle
don’t get mad at me for stating an opinion
174K is a very good number of miles to get on any vehicle. At that number of miles and 15 years old you can expect almost anything to go wrong.