The thermostat is at the front of the engine. To access it, you need to remove the thermostat housing.
If a bolt breaks, how and where it broke is a question that needs to be considered. If it broke and the threaded portion is exposed when the housing is removed, oftentimes you can grab what is left and remove it.
If it breaks inside, then you will need to drill it and remove it with an easy out.
I attached the directions below for replacing it.
Let me know if this helps or if you have other questions.,
See pics below. Note: The directions don't indicate that coolant will need to be drained from the cooling system and the upper radiator hose needs to be removed from the housing. If you don't drain the coolant, you will lose a lot of coolant.
Here is a link that is more specific. You may find it helpful.
Images (Click to enlarge)
Monday, November 21st, 2022 AT 9:07 PM