Hello and welcome to Just answer.com, Super mechanic here. About your vehicle.
If the thermostat housing came out without unbolting it, it must be broken. The thermostat and housing are all one assembly.
Thermostat Service Repair No - 26.45.01 Remove
I have the instructions for the intake in a PDF format that you can download HERE then you just click where it says “Click here to start download” Thanks