It's been said on this forum many times that it is a sure guarantee that the thermostat housing on your LS will fail in some catastrophic way at some point in time. Mine has-twice. The first time was back when the car had about 100k on it. I got stuck in the middle of nowhere Vermont, far from home and it cost me a small fortune to get that fixed. The housing cracked wide open and left me stranded. This time, it failed in my driveway but failed in a completely different kind of way. Interestingly, the thermostat housing (the part bolted to the engine) warped and broke its seal to the thermostat cover (the thermostat cover is bolted to the thermostat housing). I can see daylight through the gap. I can't tell if the part that was replaced in Vermont was a Motorcraft part or not. There are no markings stamped into the plastic. My replacement parts are due to arrive tomorrow. Friday's high temp is supposed to be 16F here in New Hampshire. Nothing is easy on this car.