Cadillac Repair: 2003 CTS that wouldnt start one day, cadillac dealer, strange noise

Question
We got home from a weeks vacation and tried to start the car.  We heard a strange noise and then nothing happened.  Towed it to Cadillac dealer.  They couldn't find what was wrong until they tore down the engine ($1200).  Now, they said there is carbon build up and they need to clean it.  It will cost $5000 to do this and put it back together.  We had a warranty from Continental and they won't pay because they say there are no "broken Parts."  Car only has $35,000 and is maintained regularly by Cadillac.  Do you see any recourse for us with this.

Answer
Other than it sounds like you are being taken advantage of by having the engine tore down WITHOUT FIRST getting a DIAGNOSIS, I see no recourse what-so-ever.

You NEVER EVER tear down an engine until you make a diagnosis of what is wrong with the engine.