Thermostat snapped

[Tommy B]

2003 LS V8 wasn't getting up to OT so I pulled the thermostat housing, found that the springload on the thermostat caused one of the plastic holddowns to break off. The resulting uneven pressure caused the thermostat to then eat away part of the seat in the outlet. I replaced the assembly so the car's back to normal for the most part, and recovered most (I believe) of the small plastic pieces from the outlet by backflushing the radiator, but never did find the black plastic holddown that snapped off from the thermostat housing. Anyone have any idea where that piece usually ends up? I'm hoping it found its way to the bottom of the block and stays there, but I have my doubts.

 

[joegr]

I wouldn't worry about where the plastic piece ended up, it won't do any harm. It's not that the spring pressure damaged the plastic. The plastic degrades with time, temperature cycles, and coolant exposure. You'll soon find the need to replace the water outlet tube (plastic pipe that comes from the block at a 45 degree angle), degas bottle, upper radiator hose, and so on. All the plastic fails at close to the same time.

http://www.lincolnvscadillac.com/forum/showthread.php?91092-GenII-LS8-Cooling-System-Overhaul

Stay away from Dorman coolant parts.