Thermostat Housing
 

2003 Mountaineer V6 142,000 AWD
Drove my car today and was pushing it on the highway. I got off the highway, came to a stop and then gunned it. A puff of whitish blue smoke came out of the back and 10 minutes later water was coming out from under the hood. I found out that the housing/piece that attaches to the thermostat housing split. It is all made of plastic. The Thermostat housing is bolted to it w/ 3 short bolts and the piece that cracked is attached to the block w 3 long bolts....
Any idea why this happened..... Never had any temp problems till today

thanx
Ron