so i changed my thermostat yesterday to a 180 degree low thermostat. Well the new o-ring I got would not stay on the housing and leaked when I installed it, so I checked the old o-ring and it wasnt broken or torn in anyway. So I installed the old o-ring again and tightened the housing down and ran the motor for about 10 mins to see if it leaked, turning the a/c on and the heat on and off. Well I drove it later that night and it worked fine, got it home and it wasnt leaking so I thought everything was ok. Well this morning when I got up I had to go to the gas station and on my way there the coolant light came on. I get back to the house and notice a puddle on the garage floor where it sat all night and now im thinking to myself the o-ring must have gave out. Well I pop the hood and start taking the 2 bolts that hold the top part of the housing on and noticed the hole housing that the thermostat sits in was cracked down the side. So now here is my question, the ford dealer wants $204 plus taxes to fix the housing, now I was looking around and noticed the housing is molded together with the whole cooling manifold(i think that is it, big black thing that sits on top of the motor) and wondering if the whole manifold needs to be changed or if I can just do the thermostat housing by itself. The service guy at ford just asked the parts guys how much the part costed and he just figured in parts and labor, so I asked him about the whole cooling manifold and he told me what I said above. any help would be greatly appreciated.