Thermostat Houising Broken

[PrimerPLus]

So my thermostat housing is broken in basically 2 pieces. The top left bolt whole has broken off and its far enough down to break the seal.

I was looking online for a new one and this is the only one I found
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I don't know if there is suppose to be a gasket too?
Anyone know the part numbers for that one and the gasket?

 

[WES_393]

If you look closely at your T-stat housing you'll see there is a depression around the mating surface. That has always told me that you should only use silicone sealant. Just make sure it fills that depression completely and install.