2005 Dodge Caravan Loss of Coolant

2005 Dodge Caravan Automatic

I leased a vehicle and two weeks after I had gotten it, the van died. I took it back to the people I leased it from and they told me that the coolant dried up and now I need a new engine. My question is, if there was coolant in the vehicle at the appropriate levels that it was supposed to be and two weeks later the van died because of loss of coolant, what would make coolant dry up in a two week time frame?