probably asking a stupid question but ,here goes,what holds the two halves of the thermostat housing together should it have a clip or adhesive?

hi all first time rr owner,and bought a 98 4.6 with a bad misfire, then found out someone had changed the right hand cylinder head gasket so the car wont start just misfires stright out the air intake it actually sounds like the timing is out any help greatly accepted :confused: