Car Zone Crooked dealership Otsago Michigan

I bought a 2005 Kia Sedona from Car Zone.  One week after buying it I found out that it was over heating.  Called the Dealership and told them.  They said it is not our problem.  Changed the themostate did not work.  Had to keep adding water every other day.  Could not find any leaks.  Took it to a repair shop and they did over 600.00 worth of work on it just to find out it had a blown block.  I had only had the Van for 7 months and drove it a total of 1 month.  Called them up and told them about it.  They told me it was not their problem.  I told them I was not going to pay for something that they knew was bad.  They came and got the Van sold it within two weeks and still want me to pay the full price of the Van.  Ripoff dealership.