Ford Repair: 1999 Ford Taurus diagnosis, ford taurus, 1999 ford taurus

Question
Steve:  My 99 Taurus just stopped running as I was accelerating away from a red light.  Until then it was running fine.  There was no sputtering or strange noises or weird smells--it just went from "on" to "off" as if someone flipped a light switch.  It would not restart, did not try to turn over at all--just a click with each key turn.  My husband had the battery tested, had it recharged, even though it already fairly well charged, cleaned all connections.  Tried again, got the same result.  We then had it towed to the dealer.  They say the oil is "sludgy" and the engine is "locked up" and needs to be replaced.  I asked them if they checked the electrical, they said no.  My question is this:  do you have any guesses as to the problem, and do you support their diagnosis?  Can a car go from running fine (really!) to "locked up" with no prior indication of a problem at all?  Thanks!

Answer
Marcia-

  Well...without seeing the car I can't endorse their diagnosis, but that certainly can and has happened.  It's especially a problem if the oil hasn't been changed for a long time or something has contaminated the oil.  Sometimes you can "unlock" the motor by pouring a small amount of diesel fluid into the oil spout, letting it sit for a while, then changing the oil.  This doesn't always work, but it's a cheap fix when it does work.  Hope this helps.

Steve